For the pastry
175g/ 6oz plain flour
75g/ 3oz cold butter
3 tbsp cold water
For the filling
1 onion, thinly sliced
½tsp dried thyme
450g/ 1lb leeks, thinly sliced
50g/ 2oz grated cheese
300ml/ ½pint single cream
pinch of nutmeg
salt and pepper
Sift the flour into a bowl and rub in butter until it resembles fine breadcrumbs. Make a well in the centre.
Pour the water into the well and combine well. Wrap in cling film and chill for 30 minutes.
Grease flan dish. On lightly floured surface, roll out dough to about 3mm thick. Cut to fit and place in dish. Prick base with fork and chill for 30 minutes.
Preheat oven to 190˚C/ Gas 5. Line pastry case with foil and fill with baking beans. Bake for 6-8 minutes until golden brown at edges. Remove foil and baking beans and bake for a further 2 minutes until base appears dry. Transfer to wire rack to cool and reduce oven temperature to 180˚C/Gas 4.
Melt butter in a large pan. Add onion and thyme and cook until onion is just softened.
Add leeks and cook for about 10 mins until they are soft and tender.
Place the leek mixture in the pastry case and sprinkle over the cheese.
Beat the eggs with the cream and nutmeg and season. Pour into pastry case.
Bake for 20-25 minutes until set and golden.