Welsh onion cake with caerphilly

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

  • Prep:30 mins
    Cook:1 hrs 5 mins
  • Serves 6
  • Easy

Nutrition per serving

  • kcal 542
  • fat 36g
  • saturates 22g
  • carbs 41g
  • sugars 9g
  • fibre 7g
  • protein 11g
  • salt 0.9g


  • 200g butter, plus extra for the tin
  • drizzle of oil
  • 3 large onions, thinly sliced
  • 1 leek, sliced
  • 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)


How to use up leftovers

Fry leftover wedges of Welsh onion cake until crispy and hot, then serve with bacon and poached eggs for a filling brunch. Alternatively, make leek and potato pasties. Roughly chop leftover Welsh onion cake, and pile onto the centre of circles of ready-rolled shortcrust pastry. Brush the edges with beaten egg, then crimp together. Brush the tops with more egg, put on a baking sheet and cook at 200C/180C fan/gas 6 for 25-30 mins until golden brown.


  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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