Traditional Welsh Onion Cake

A Welsh onion cake on a serving plate with a dinner plate in background with vegan sausages and peas and corn.

Course: Dinner, Side Dish

Cuisine: Welsh

Prep Time: 25

Cook Time: 1 15

Total Time: 1 40

Servings:

Calories: 361kcal

Author: Jacq

Welsh Onion Cake is a traditional family favourite that is prepared with a few staple ingredients.

It is deliciously budget-friendly and can easily be the main for a festive occasion, a side dish, or a mid-week meal.

If preferred you can bake individual onion cakes using ramekins or small pie dishes, however do adjust the cooking time as they may cook more quickly.

Print Recipe

US Customary - Metric

Equipment

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

Ingredients

Saute onions:

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]

Onion cake:

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]

Instructions

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!

Notes

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.
The potatoes can be replaced 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 vegetables, as well as potatoes, would look very nice.
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.
Additons: 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.
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.
As we are a plant-based family recipe blog all our recommendations will be for vegan cheese, margarine, butter, etc. However, if you have different dietary requirements you can use your usual ingredients.

Nutrition