* Boil potatoes with their skin on until tender. Peel, and mash them in a food mill or with a potato masher, while still hot.
* Preheat oven to 350 F (175 C).
* Transfer to a bowl the mashed potatoes, the egg, 1 tablespoon of the butter, the parmigiano, mozzarella, ham, parsley, lemon rind, nutmeg, milk, salt, and pepper.
* Mix with a spatula to thoroughly combine all the ingredients.
* Brush with butter a round oven pan, approximately 8 inches (20 cm) in diameter.
* Spread with some of the breadcrumbs.
* Transfer the potato mixture to the pan
* Level it with a spatula.
* Top with the bread crumbs.
* Make a design on the surface of the potatoes with the prongs of a fork.
* Top with the remaining 1 tablespoon diced butter.
* Bake for about 30 minutes, until the surface is golden. Serve hot.
* 2 lb (900 gr) russet potatoes
* 1 egg
* 2 tablespoons (30 gr) butter, diced
* 2 oz (60 gr) parmigiano reggiano cheese, grated
* 2 oz (60 gr) mozzarella cheese, diced
* 2 oz (60 gr) cooked ham, diced
* 2 tablespoons Italian parsley, chopped
* grated rind of 1 lemon
* pinch of nutmeg
* 1/2 cup (120 cc) milk, or heavy cream
* salt and pepper
* 2 tablespoons bread crumbs