Leeks and Potatoes au Gratin

12 leeks                               

½ cup grated cheese

6 potatoes                          

Bread-crumbs

1 cup Béchamel or Veloute sauce

            Salt and pepper

Cook the leeks in boiling water; boil and slice the potatoes; arrange the vegetables in a baking-dish, and pour the white sauce over them. Add the cheese, bread-crumbs and seasoning, and bake (350 F.) for fifteen minutes.