Noted as a personal favourite dish of cook Bobby Freeman (author of the agenda-setting guide to Welsh cuisine First Catch Your Peacock), teisen nionod, or onion cake in English, is a simple, hearty combination of potato and onion that adds a Welsh flavour to any dinner.

Though details about the origin of the dish are scarce, onions are thought to have arrived in Britain with the Romans way back in AD43, while potatoes have been cultivated and eaten in Wales since at least the 18th century. 

Intriguingly, the dish bears a striking resemblance to the French meal pommes de terre de boulangère (baker’s potatoes), traditionally made in the cooling bread ovens of French bakeries.

In fact, the Welsh dish may have been frequently prepared with French onions, owing to the practice of onion sellers from Brittany (known colloquially as “Johnny Onions”) coming across to Wales to peddle their wares, a custom that dates back to the early 19th century.

The dish is an accompaniment to a lunch or dinner, typically paired with a joint of meat. Often this type of meal would have been eaten on a Sunday lunchtime after church, as part of the – still popular – British tradition of a “Sunday roast”.

Teisen nionod would have been traditionally prepared in a cake tin, and – though not essential – this remains a good cooking method for the dish. Using a cake tin means that, once cooked, the onion cake can be flipped onto a serving dish and cut into slices to serve. It’s worth noting it will be easier to get the cake out in one piece if you let it cool in the tin before removing it, then reheating to serve.

It’s best to slice the onions and potatoes very thinly. I use a mandoline, but a food processor also works well.

If you are cooking this in the same oven as a roasting meat joint, feel free to cook it at a lower temperature – it will just take longer to cook through. If so, I highly recommend placing your joint on a rack above your teisen nionod (once you’ve removed the foil) so that its juices drip down onto the cake.

Serves: 4 (as a side dish) | Prep time: 20 minutes | Cook time: 1 hour 30 minutes 

Ingredients

100g butter, melted, plus extra for brushing

1kg potatoes, thinly sliced

500g onions, thinly sliced

80ml beef, lamb or chicken stock (optional)

Salt and pepper

Method

Step 1: Preheat the oven (220C; fan 200C; gas 7). Wash the sliced potatoes briefly in cold water and dry on a clean tea towel.

Step 2: Put the potatoes in a bowl and mix with salt, pepper and the melted butter. Butter a shallow baking dish and layer up potatoes and the sliced onion, finishing with a neat layer of overlapping potatoes.

Step 3: Pour over the stock (if using) and cover tightly with foil. Bake in the oven until a sharp knife goes through with minimal resistance, this should take around an hour. 

Step 4: Remove the foil and return to the oven. Turn the heat down (180C; fan 160C; gas 4) and bake for another 20-30 minutes or until golden brown.

This recipe was researched and tested by chef Alex Vines. Alex developed his signature “simple yet attentive” cooking style during a decade working in renowned London restaurants. Originally from Cardiff, Alex champions the use of seasonal and local produce, mirroring the principles of traditional Welsh recipes. Follow Alex on Instagram.