Or, in English, leek tart.
This is one of those classic French open tarts, that we often call a quiche in the UK nowadays, but in France these are generally called tartes.
It is a simple thing to make.
Line a buttered pastry ring with a removeable base with short pastry, prick the bottom with a fork and blind bake until the pastry has firmed up and taken some colour.
It is worth it if you don’t trim the pastry before the initial blind bake, because of shrinkage. Once the pastry case has cooked down, you can trim the edges with a sharp knife.
Make the filling as follows;
Beat two eggs and two egg yolks into a bowl with half cream or crème fraiche and half milk, salt and pepper. I tend to judge the quantities by eye, because it is tricky to know exactly how much you will need.
Sauté three finely sliced leeks in butter with a little oil until they are softened but not browned. You want to avoid them taking on too much colour, because this makes them go bitter.
Spread the leeks evenly over the base of the pastry and sprinkle with a good handful of grated Emmenthal or similar cheese; Gruyère or Comté would be equally good.
Then carefully pour in the eggy custard mixture until it fills the case to the edges.
Bake on the middle shelf of an oven at 170C until the custard is set and golden on top.
When it is cool, it should be easy to remove from the pastry ring.