Cut 50g butter and 50g veg fat into small cubes and add 175g plain flour in a bowl. Rub together until the mixture resembles breadcrumbs.
Beat an egg yolk and add 2tsp caster sugar and some water - add this to the mixture to form a soft dough. Wrap and chill in the fridge for at least 30 mins.
Lightly oil the 8" flan dish. Roll out the pastry onto a lightly floured surface, and place in the dish - press gently into the edges and trim the edges with a blunt knife.
Whisk 2 eggs and an egg yolk with 25g caster sugar. Warm 300ml (1/2 pint) milk in a saucepan and pour into the egg mixture, then whisk together. Use a sieve to pour the mixture through into the pastry case, sprinkle the top with some nutmeg and put the flan dish onto a baking tray.
Bake in the oven at gas 6 or 200C for 15 mins, then turn the temp down to gas 3 or 170C and bake for another 30 mins. Let it cool and then enjoy!