1. Wash and cut the leeks into pieces.
2. Cook them in a covered sauté pan with the butter
3. and a little water for about 20 minutes.
4. Once cooked, mash them with a fork.
5. Roll out the dough in a pie dish, prick it with a fork.
6. Sprinkle with breadcrumbs and spread the mashed leeks.
7. Beat the eggs with the cream and milk, salt, pepper, and a pinch of nutmeg.
8. Pour over the leeks and sprinkle with breadcrumbs.
9. Bake for 40 minutes in a preheated oven at 220°C (425°F).