Potato gratin in pan

Welsh onion cake with caerphilly

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(3 ratings)

Prep: 30 mins Cook: 1 hr, 5 mins


Serves 6

Take this Welsh classic to the next level by adding sharp, salty cheese and sweet leeks. It’s the perfect dish for St David’s Day or an easy family dinner

Nutrition and extra info

  • Gluten-free
  • Vegetarian

Nutrition: per serving

  • kcal542
  • fat36g
  • saturates22g
  • carbs41g
  • sugars9g
  • fibre7g
  • protein11g
  • salt0.9g
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  • 200g butter, plus extra for the tin



    Butter is a dairy product made from separating whole milk or cream into fat and…

  • drizzle of oil
  • 3 large onions, thinly sliced



    Onions are endlessly versatile and an essential ingredient in countless recipes. Native to Asia…

  • 1 leek, sliced



    Like garlic and onion, leeks are a member of the allium family, but have their own distinct…

  • 1kg floury potatoes, such as Maris Piper or Désirée, peeled and thinly sliced (use a mandoline or the fine slicing blade of a food processor)
  • 150g Caerphilly cheese, crumbled (or another sharp, crumbly cheese)


  1. In a large pan, heat a knob of the butter with a drizzle of oil. Once the butter is foaming, add the onions, leek and some seasoning and cook for 15 mins until the onions are soft and sticky, stirring occasionally. Butter a 22cm cake tin or baking dish (alternatively, you can assemble the cake in the pan you’re already using if it’s ovenproof).

  2. In a separate pan, melt the remaining butter. Toss the sliced potatoes with the melted butter and plenty of seasoning. Heat oven to 200C/180C fan/gas 6.

  3. Arrange the potato slices over the base of the dish in a spiral or in concentric circles. Top with some of the onion mix, sprinkle over a layer of cheese and continue layering, finishing with a final round of potato slices. Press down firmly with your hands to compact the layers. Bake for 45-50 mins until the potatoes are golden brown and tender; cover with foil if the cake starts to take on too much colour. Turn out onto a plate to serve.

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