Creamy cheddar and fish pie
400g plain flour, plus extra for dusting
1 tsp fine salt
½ small bunch of thyme, leaves picked
½ tbsp English mustard powder
180g cold unsalted butter, cut into cubes
2 large eggs, beaten
steamed greens, to serve
For the filling
1 potato (about 270g), chopped into 3cm chunks
1 tbsp olive oil
2 leeks, finely sliced
3 tbsp plain flour
400ml whole milk
100ml double cream
100g mature cheddar, grated
3 tsp Dijon mustard
¼ bunch of chives, finely chopped
200g skinless salmon fillet, cut into chunks
200g skinless smoked haddock fillet, cut into chunks
100g raw king prawns, peeled
Tip the flour, salt, thyme and mustard powder into a food processor and pulse briefly. Add the butter and pulse again to a fine breadcrumb texture. Add half the egg and 1 tbsp cold water and pulse until it comes together into a dough (you can add up to 1-2 tbsp more water if it’s dry). Tip the dough onto a work surface and knead briefly. Wrap and chill for 30 mins.
To make the filling, cook the potato in a pan of boiling water for 8-10 mins. Drain and leave to steam-dry. Heat the oil and butter in a large frying pan over a medium heat, and fry the leeks for 5 mins. Stir in the flour and cook for 2 mins, then add the milk, a little at a time, stirring between each addition to combine. Add the cream, cheese and mustard, and cook for 1-2 mins more until the cheese has melted. Stir in the chives and season. Remove from the heat and leave to cool for 15 mins.
Heat the oven to 220C/200C fan/ gas 8. Gently fold the salmon, potato, haddock and prawns into the creamy leek mixture, then spoon into a 27cm round pie dish. Roll the pastry out on a lightly floured surface to the thickness of a £1 coin. Drape the pastry over the pie, then trim the excess. Crimp the edges, then shape the off-cuts to decorate the top, if you like. Brush with the remaining egg, then bake in the centre of the oven for 35-40 mins until golden. Serve with steamed greens.