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Published 16/03/2026
0:55
Serves 6
Medium

Leek, cheese and walnut gratin

Sweet leeks, crunchy walnuts and plenty of melted cheese come together in this rich, comforting side dish. Baked until bubbling and golden, it’s an indulgent addition to any roast or special supper.

To add some extra crunch, top with breadcrumbs for that golden, crisp crust.

What you'll need...

  • 1 tbsp olive oil
  • 4 large leeks, washed and cut at an angle into 3cm slices
  • 2 garlic cloves, finely sliced
  • 50ml white wine (optional)
  • 60g unsalted butter
  • 60g plain flour
  • 500ml whole milk
  • 1 tsp English mustard
  • 50g parmesan or veggie equivalent, grated
  • 50g mature cheddar, coarsely grated
  • 125g ball mozzarella, torn
  • 50g smoked cheese, grated
  • 1/2 tsp cider vinegar
  • 75g walnut halves

Method

  1. Heat the oven to 180°C/160°C fan/gas 4. Heat the oil in a large frying pan over a medium heat, then add the leeks and garlic and cook for about 10 minutes until starting to soften, stirring regularly. Add 50g of the walnuts and the wine, if using, and simmer for a few minutes.

  2. Meanwhile, make the cheese sauce. Melt the butter in a saucepan over a medium heat, stir in the flour to form a paste, then gradually add the milk, stirring until smooth. Bring to the boil to thicken, then stir in the mustard and cheeses, reserving a handful for the topping. Season to taste and add a dash of vinegar.

  3. Stir the leeks into the cheese sauce, transfer to an ovenproof dish and scatter over the reserved cheese and remaining walnuts. Bake for 30 minutes until bubbling and golden on top.

Shop the tools you will need

Secondary image for image of Oak Butchers Block Large 46 cm x 36 cm x 4 cm Main image for image of Oak Butchers Block Large 46 cm x 36 cm x 4 cm

£149.00

Secondary image for image of Ash Wood Serving Board Large Sky Blue 50.8cm x 27.9cm Main image for image of Ash Wood Serving Board Large Sky Blue 50.8cm x 27.9cm

£35.00 £24.50

Secondary image for image of Elite Tri-Ply Uncoated Cookware Set 6 Piece with 20cm Saucepan Main image for image of Elite Tri-Ply Uncoated Cookware Set 6 Piece with 20cm Saucepan

£440.00 £340.00

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