1: Wash and slice 2 leeks thinly. Peel and chop 1 shallot. Pour 4 tablespoons olive oil into a pan on medium heat. When it's hot, add the chopped shallot, salt and pepper, and cook for one or two minutes.
2: Add the sliced leeks, mix well, cover and cook for about 10 minutes...
3: ...until leeks are soft, but keep a pretty green colour. Salt and pepper only now.
6: Coat the whole surface with butter, using a brush.
7: Put the sheet into your mould or dish, buttered side down. Trim off the surplus, and use the trimmings to completely cover the inside of the mould.
8: Do this with 2 or 3 layers of filo pastry, each time buttered side dowm. Finally butter the upper surface of the last sheet (which will be buttered both sides).
10: Put the leeks into the pastry case in an even layer.
11: Pour in the mixture.
12: Put slices of cheese on top.
13: Put in the oven for about 30 minutes.
14: Remove when golden brown. It's ready.
Remarks
You can use any cheese you like, but I advise you to use a soft strong-flavoured cheese: Morbier, Maroilles or Munster (for French examples), or any good goat's cheese, etc. If you love plenty of crust, add one or two more layers of filo pastry.