Boxing Day Cheese, Potato & Pickle Slab Pie

1. Preheat the oven to 190C/(fan 170C) Grease your chosen pie dish or sheet pan with 25g of butter. Dust your surface with the flour, remember to dust the rolling pin too. Set aside a third of the pastry for the lid (approx. 160g), roll it out slightly larger than the size of the dish then pop it back in the fridge on a lined baking sheet.

2. Roll out the rest of the pastry to line the dish, ideally to the thickness of a £1 coin. Using a fork, prick the base of the pie. Line the pastry case with baking paper and fill with baking beans or uncooked rice. Bake for 15mins, leave to cool.

3. Meanwhile, place the potatoes in a large saucepan of cold water and bring to the boil. Simmer for 10 mins, drain and let them cool. Sauté onion in a pan with a small amount of butter.

4. Fill the pastry case with a third of the potatoes, leaving small gaps. Add blobs of the Sweet Sandwich pickle, butter cubes, onions and the two types of cheese. Add 2 more layers.

5. Add the pastry lid and seal the edges by crimping, brush the top with the beaten egg. Bake for 30-35 mins, until glowing golden on the top.