Welsh Onion Cake is a traditional family favourite that is prepared with a few simple ingredients - potatoes, onions, cheese, and seasonings. It is a very versatile recipe as its easy to prepare as vegan and plant-based, and its also ideal for gluten-free diets, as well as no-oil diets as we have included easy tasty swaps. Welsh Onion Cake is just good family home-cooking and is deliciously budget-friendly. It can easily be the main for a festive occasion, as well as a side dish, or a mid-week meal.
A Welsh Onion Cake is a a good example of Welsh Country Cooking at its best - simple budget-friendly wholesome ingredients cooked to tasty homely perfection. The potatoes are butter soft, creamy, and crisp, and the onions are sweet, carnalized and juicy, and the cheese is well...nice and cheesy!
🧅 What is a Welsh onion cake?
A Welsh Onion Cake is a homely recipe that hails from the country cooking of the rural Welsh Farmhouses and the cake was typically cooked alongside a roast, making thrifty use of the oven. The humble ingredients - onions, potatoes and cheese - reflects the staple ingredients available to people during the different seasons and times of hardship. Onion cake could be easily prepared with locally sourced ingredients, making it a budget-friendly but filling meal.
While not exactly a cake in the sweet sense, this savoury rustic pie-like bake is prepared with a few everyday ingredients- sliced potatoes and onions, and it's usually seasoned with salt, pepper, and perhaps a bit of butter. Some recipes add cheese whereas others like to include leeks, fresh herbs, or sliced tomatoes over the top of the cake near to the end of cooking.
For information about Traditional Welsh Cooking do have a look at this interesting article from historic-uk.com.
🍰 Why is it called a cake?
For many traditional British recipes the term 'cake' isn't restricted to sweet baked recipes as historically the term cake has been used for anything, sweet and savoury, that takes a particular form or shape when cooked - think of potato cakes, fish cakes, oat cakes, soul cakes, for example. Also, the onion cake is usually baked in a cake pan and is served in slices similar to a cake so that also answers the question!
🌍 More vegan Welsh recipes
We are loving cooking and baking traditional Welsh recipes made veggie! So more recipes are going to be added as Welsh cooking is full of hearty, homely, family favourite comfort foods that are ideal for enjoying over the chillier months.
So far we have enjoyed bowls of this tasty sustaining meat-free Welsh Cawl Soup followed by a dessert of hot reheated Welsh Apple Cake and hot custard or a drizzle of plant-based cream, although the kids do prefer a few scoops of ice-cream with the apple cake instead. Reheating the apple cake crisps up the edges and results in an apple pie vibe!
For breakfast, snack, or mid-morning munchies or elevenses' a few warmed up Bakestone Cakes split in two and buttered are just a delicious treat. Bake a batch and pop them in the freezer and then you can enjoy one or two whenever you like.
🔪 How to prepare
All the best recipes are traditional, require only a few ingredients, yet are packed with tasty textures and flavours! Our ancestors had to make do with much less choice of ingredients that we do now, but goodness they sure made the best of a few local ingredients by elevating them into delicious dishes.
Onions and potatoes are the star of the show for this Welsh country recipe, along with - salt and pepper, vegan cheese, a cup of vegetable stock, and optional oil and margarine.
The vegan cheese is also optional, as it can be switched out for nutritional yeast flakes.
We initially saute the onions in a small amount of olive oil but if preferred you can replace this with a quarter cup of vegetable stock or broth.
We also use two teaspoons of vegan-friendly margarine or butter but this can also be replaced or omitted. If omitting the margarine we suggest stirring through one tablespoon of white miso paste through the vegetable stock that is poured into the onion pie before it is baked as this will add extra umami flavours minus the additional fat.
Finally, as we are a vegan family recipe blog we always recommend vegan-friendly ingredients such as - vegan butter, margarine, and plant-based cheese - however, if you have different dietary requirements do feel free to use your everyday ingredients.
Step 1: First gather all your ingredients. Next slice the onions into rings, the potatoes into thin slices, and grate the vegan cheese. You can use a mandolin to slice the potatoes if preferred.
Line a cake pan with parchment paper, we used a cake pan with a loose-bottom so that the baked cake could be removed more easily. Our cake pan measured 8 inch diameter and 3 ½ inch high.
Step 2: Heat the oil in a fry pan or skillet and cook the onions over a medium heat for 8 minutes stirring frequently.
Step 3: Add two layers of potato slices to the bottom of the cake pan. Cover with a layer of onions and season with salt and pepper. Dot a teaspoon of margarine over this layer.
Step 4: Sprinkle some vegan cheese over the layer.
Step 5: Repeat the layers but just add one layer of potatoes and omit the margarine for the middle layers. Season each layer with salt and pepper.
Step 6: Finish the onion cake with a layer of grated cheese and dot a teaspoon of margarine over the top.
Step 7: Drizzle 240 millilitres [1 cup] of vegetable stock over the cake being careful not to disturb the cheese. Cover the top of the cake pan with kitchen or Aluminium foil.
Step 8: Bake for 45 minutes before removing the foil and baking for a further 30 minutes or until the potatoes are soft and the top is golden and crispy. If you use a mandolin your potato slices will be quite thin so the cake will bake faster and you can reduce the cooking time.
Step 9: Allow the onion cake to sit for 5 minutes to settle before removing from the cake pan or slicing a piece. If any of the layers falls apart while slicing and lifting they can be easily pushed back!
🧾 Recipe notes
Leftovers can be stored, covered, within the refrigerator for up to 3 days. An option is to pack leftovers into individual ramekin dishes or similar and cover the top with food wrap until ready to reheat. Adding the leftovers to individual serving dishes makes it easier to reheat and you'll know how many portions you have for meal planning. Alternatively, scoop the leftovers onto a plate and cover before refrigerating.
You can either freeze the entire baked onion cake for 2-3 months within the baking dish, well wrapped in food wrap, or freeze smaller portions of onion cake packed into a smaller baking dish/s. Thaw completely and bring the baking dish up to room temperature before reheating to avoid thermal shock - which refers to the potential of the dish cracking due to sudden change in temperature.
Leftovers can be added to a baking dish or placed onto a baking tray lined with baking paper, and reheated in a hot oven for 25 minutes or until piping hot throughout. The tops of the potatoes and onions will become even more crispier and more caramelized as its reheated so leftovers are very tasty!
Yes, this onion cake can be easily prepared as gluten-free. Be sure and use a gluten-free vegetable stock, and if using vegan margarine and vegan cheese then check that those are also free from gluten ingredients.
For an onion cake, starchy potatoes like Russet, King Edward, Maris Piper, Desiree, and Red potatoes, are generally good choices as they hold their shape while absorbing the flavours of the other ingredients.
However, we used ordinary potatoes that were simply labelled 'white potatoes' from our local Co-Op supermarket as these are relatively inexpensive compared with the other varieties, and they do hold their shape well while being quite delicious.
Yes, using a mandolin is a great way to achieve evenly thin slices of potato, making for quicker cooking and a well-structured onion cake.
Although do be cautious while using the mandolin to avoid any accidents, a safety glove is a good precaution.
Using a mandolin is not only a great time saver but it is also a useful tool to use if you have joint issues as it can be much easier on your wrists and hands!
We used yellow onions as those are the most commonly available onions in UK supermarkets, and can also be found in other countries. However, if you have an onion preference then you can use that type.
Yes, for an oil-free onion cake you can saute the onions in a small amount of vegetable stock or broth, adding a little more stock whenever required.
The margarine can also be omitted and instead if you have any white miso paste available you can whisk a tablespoon of the paste through the hot vegetable stock that is poured over the assembled onion cake before baking.
Doing so will add extra umami savoury flavours without the additional calories and fat.
Any vegan cheese that melts well is perfect for the onion cake. We like to use the Violife Cheddar Flavour block of vegan cheese [400gram block] as our local wholefoods shop stocks it and its cheaper than our buying a different type from our local supermarket.
Violife also do the same block of vegan cheese but in a smoked flavour which is one of our favourites, and it would be quite delicious with our onion cake.
We purposefully kept the amount of cheese to the minimum with our onion cake recipe as the vegan cheese is quite expensive and we wanted to keep it to enjoy in other recipes, but of course if you prefer you can add more vegan cheese to the recipe.
The best replacement is to add 1-2 tablespoons of nutritional yeast flakes to each of the layers as well as the top layer as this will add a nice cheesy flavour.
Nutritional yeast flakes are a deactivated yeast that provides a cheese-like flavour and is often used in vegan and plant-based cooking as a seasoning or cheese substitute, you may also have heard it being called ''nooch''.
Yes, you can replace the potatoes with a similar textured vegetable such as sweet potatoes, parsnips, celeriac, or swede [also known as rutabaga in the US and turnip in Scotland!].
An onion cake created with a mixture of different root veggies, as well as potatoes, would look pretty nice.
Just keep in mind the different cooking times for each vegetable and adjust times as necessary, and to try and slice all the veggies the same thickness!
Feel free to add fresh or dried herbs like thyme, sage, chives, or rosemary to each layer for added flavour.
Some traditional recipes for onion cake also include one or two leeks along with the onions so you could add some leeks if liked.
The potato slices are cooked when you can poke a knife or fork, or long toothpick or a metal kebab stick as we like to use, easily through the potatoes to the bottom of the cake pan.
The exact cooking times will depend on the type of potatoes you use as well as the thickness the potatoes have been sliced. Potatoes prepared on a mandolin will be very thin so will cook through much quicker compared to hand cut potatoes.
The onion cake is even more tasty when the topping is crisp and golden so once the potatoes are soft but not golden, do continue to bake until the topping has crisped up. Again the cooking times will vary so use our timings as a guide.
If you're using the oven for another dish, you can start the onion cake at the bottom of the oven and then move it nearer to the top when the foil is removed.
This might alter the cooking time slightly but can be a good energy and money saver.
If your other dish requires a lower temperature your onion cake will be fine cooking under it as it will just require a little longer to cook.
We use an 8 inch diameter loose-bottomed cake tin for this onion cake as the loose bottom means its easier to remove the entire cake from the pan at the end of baking. Our cake pan is 3 ½ inch high so deep enough to contain the layers.
You can use a similar circular, square, rectangle, baking pan, tin, or dish, preferably with a loose-bottom.
However, if a loose-bottomed dish is not available then just use a deep casserole dish about the same diameter and scoop servings of the cake out at the end.
Yes, that would result in very cute wee onion cakes! If you have them available do use loose-bottomed mini cake or pie pans as that will result in the cakes being easier to remove from the tins.
However, you could use small ceramic pie dishes or ramekins and simply serve the onion cakes in the dishes directly on to the dinner plate. Or flip the dishes over and serve the bottom end of the cake upright!
Once the onion cake is unveiled you will see tasty vegetable stock and veggie juices running out the bottom so this could be regarded as a self-saucing cake! We used an OXO meat free chicken flavour cube to prepare the stock so it did contribute a nice flavour. We enjoyed the onion cake with vegan sausages [Co-Op Gro Sizzlin' vegan sausages], peas and corn, and gravy.
Instead of one large onion cake an alternative idea is to use mini pie pans or ramekins and serve the oven dish directly on the dinner plate along with sides.
Mini onion cakes could be baked and stored in the refrigerator for a few days before a special meal. Or wrap the baked onion cakes along with the baking dish and freeze for a future festive main or side. To prepare thaw the onion cake to room temperature before baking to avoid 'thermal shocking' the dish in the oven [the sudden change in temperature can stress some materials such as glass and ceramic and result in the dish cracking] although this is not an issue for metal pie pans.
👪 More family dinner ideas
Here is a few of our family favourite dinners that feature the humble delicious potato. We love using potatoes as the star of the show as they are wholesome, cheap, versatile, and just taste nice!
For a British old-school dinner favourite you can't beat this vegan version of a Cheese, Onion and Potato Pie which when chilled is a great picnic and pack-lunch pie. Another brilliant picnic pie is our British Homity Pie which is a vintage classic dating back to the Land Girls of the 1940s!
For special occasions especially for, Hogmanay or New Years Dinner we love our Vegan 'no-meat' and Potato Pie as its the best comfort food and so hearty and savoury.
For every-day mid-week meals our Vegan Scottish Mince and Tatties is a frequent visitor to our slow cooker!
***please note: for US measurements click the 'US customary button' within the recipe and the measurements will switch to tablespoons, cups, and ounces.***
Traditional Welsh Onion Cake
- non-stick skillet or frying pan
- deep cake pan or similar 8 inch diameter x 3 ½ inch high, use one with a loose bottom if available
- greaseproof or baking paper
- Aluminium foil
- Baking tray
- 1 tablespoon olive oil [or your usual oil, or replace with ½ cup of vegetable stock or broth for an oil-free dish]
- 500 grams onions [about 2 medium-large onions, peeled and sliced into thin rings, if onions are quite large half the rings]
- 950 grams potatoes [keep the skins on if unblemished, slice as thin as you can or use a mandolin]
- 2 teaspoons vegan margarine [or vegan butter, or omit this ingredient and see recipe notes for substitute]
- 100 grams vegan cheese [grated/shreds, can replace with nutritional yeast flakes - a tablespoon or two for each layer] [you can use more cheese if preferred]
- 240 mililitres vegetable stock [we used one meat-free chicken flavour OXO cubes dissolved in boiling water]
Prepare the onions:
- Heat the oil in the skillet pan over a medium heat. Add the onions and cook for 8 minutes, stirring frequently.[Alternatively, heat ½ cup [120 millilitres] of vegetable stock and saute the onions, adding small amounts of extra stock whenever required to prevent the onions sticking to the pan]1 tablespoon olive oil, 500 grams onions
Assemble the onion cake:
- Preheat the oven to 190 Fan, 210 C, 410 Fahrenheit, Gas 6.
- Grease the cake pan with margarine and line with parchment paper.
- While building up the onion cake layers keep in mind the amount of your ingredients and the size of your cake pan so that you can evenly distribute the ingredients throughout the layers.
- Add two layers of potato slices to the bottom of the cake pan and cover with some of the onions. Season with salt and pepper, and dot one teaspoon of margarine over the layer [although the margarine is optional]. Sprinkle some of the cheese over this layer.950 grams potatoes, 100 grams vegan cheese, 2 teaspoons vegan margarine
- Repeat with another layer of potatoes slices, onions, salt and pepper, and some cheese, until you get to the top final layer.
- For the final layer end with a layer of potatoes, salt and pepper, cheese, and the second teaspoon of margarine dotted over the top layer.
- Drizzle over the vegetable stock and it will pour down through the layers, although be careful not to disturb the top cheese layer too much.240 mililitres vegetable stock
- Cover the top of the cake pan tightly with some Aluminium or kitchen foil, and place the cake pan on top of the baking tray, and place into the oven on the middle shelf or the shelf close to the top of the oven. Bake for 45 minutes.[Although, if your using the oven for a different dish you could start with the onion cake at the bottom of the oven and then move it up nearer the top when the foil is removed for the topping to crisp up. This may increase the initial baking time but cooking several dishes at once can be great energy and money saver]
- After 45 minutes, switch the heat up to 200 Fan, 220 C, 428 Fahrenheit, or Gas 7, and remove the foil lid from the cake pan. Bake for another 25 minutes or so until the potatoes are soft and the top is nice and crispy golden. The exact times will depend on your oven and the thickness of the sliced potatoes. If you used a mandolin the potatoes will be much thinner and so will cook quicker.
- Once the onion cake is removed from the oven allow it to sit for 5 minutes to settle before slicing. If you baked using a loose-bottomed cake pan, you can sit the cake pan on top of a can of food and then carefully slide the cake sides down. Use a tea towel or oven mitts to help as the cake pan will be hot!We didn't attempt to remove the cake base or parchment paper from the cake and instead for an easier life just added it all to the serving plate!
- Use a sharp knife to carefully cut a slice of onion cake and a flat wide spatula or fish slice utensil to scoop up the cake. If any of the layers are displaced just push them back together!
- Nutritional information is for guidance only and is not an exact calculation as ingredients vary.
- Store leftovers, covered, within the refrigerator for up to 3 days.
- Or freeze for 2-3 months.
- Leftovers can be added to a baking dish or placed onto a baking tray lined with baking paper, and reheated in a hot oven for 25 minutes or until piping hot throughout. The tops of the potatoes and onions will become nice and crispy and more caramelized as its reheated so leftovers are very tasty!
- For an oil-free onion cake you can saute the onions in a small amount of vegetable stock or broth, adding a little more whenever required.The margarine can be omitted and instead if you have any white miso paste available you can whisk through a tablespoon of the paste through the hot vegetable stock that is poured over the assembled onion cake before baking. Doing so will add extra umami savoury flavours without the additional calories and fat.
- We used Violife Cheddar Flavour block of vegan cheese [400gram block].
- The vegan cheese can be replaced with 1-2 tablespoons of nutritional yeast flakes sprinkled over each layer as well as the top layer as this will add cheesy flavours.
- For a gluten-free onion cake use a gluten-free vegetable stock, and check that your margarine and vegan cheese are also free from gluten-ingredients.
- We used ordinary potatoes labelled as - white potatoes - sourced from our local Co-Op supermarket [UK].
- Our onions were ordinary supermarket ones - yellow onions.
- Onion cakes can be prepared in individual mini pie or cake tins, or ramekins, and served directly from the dish along with sides. Adjust the cooking times as they may cook faster. Leftovers, can also be packed into ramekins or individual baking dishes and stored, then reheated as this way you can see how many portions you have
- For more useful information do have a look at our recipe notes and FAQ sections above this recipe.
- As we are a vegan family recipe blog all our recommendations will naturally be for vegan cheese, margarine, butter, etc. However, if you have different dietary requirements you can use your usual ingredients.
Prepared our Welsh Onion Cake recipe? Do pop back and drop us a comment below and click the star ratings, as we would love to know how you got on. It's very much appreciated, thanks so much! Jacq x