potatoes:
500 g potatoes
30-40 g butter
75 g Pecorino and/or Grana Padano cheese, grated
1-2 tb flat-leaf parsley, chopped
1 egg, lightly beaten
lemon juice and lemon zest, to taste
salt, pepper
milk, if needed
filling:
125-150 g mozzarella, diced
2 tb olive oil
salt, pepper
in addition:
breadcrumbs, butter
Boil potatoes in their skins until tender. Peel and pass potatoes through a ricer while hot. Let cool down a few minutes, then mix in the other ingredients. Mash together until creamy. Grease a baking pan (20 cm diameter) and coat with breadcrumbs. Turn half of potato mixture into the pan. Mix mozzarella with oil, salt and pepper, spread over potatoes. Cover with remaining potato mixture. Sprinkle with breadcrumbs and small flakes of butter. Bake in preheated oven at 180 deg C for 45 minutes or until golden brown.