Ultimate quiche lorraine

Method

1. In a mixing bowl, rub the flour, butter and a pinch of salt together with your fingertips until it has the texture of breadcrumbs. Add the egg yolk and water, bring together to form a smooth ball, then wrap in cling film and chill for 30 minutes.
2. On a lightly floured surface, roll out the pastry to a rough 30cm circle. Lay over the tart tin to line the base and sides, pushing the pastry into the edges of the tin. Trim any excess overhanging dough, then prick the pastry base all over with a fork. Chill for 30 minutes (see tip).
3. Meanwhile, make the filling. Heat the butter in a large frying pan and add the onions. Cook until golden and soft, then scatter over the base of the tart, along with the ham.
4. Heat the milk in a saucepan until just steaming. In a separate pan, whisk the eggs with the cayenne pepper, nutmeg and a pinch of salt.
5. Heat the oven to 190°C/170°C fan/gas 5. Put the egg pan over a gentle heat and whisk in the hot milk until combined, then cook until thickened and pale (about 8 minutes – see tip). Pour the mixture over the onion and ham in the tart, then bake for 30-40 minutes until just set and turning golden at the edges. Cool in the tin before removing and slicing.