Let's go down to Salento in the Puglia region of Italy where we find a recipe for potato pie, a very tasty dish with an onion and tomato sauce fllling. This is the classic filling but there are variants which use anchovies, tuna, or ham and cheese. In Salento it is often prepared for a picnic or a Sunday spent at the beach. It's very versatile and can be served either as a main or side dish, hot or cold.
Peel and boil the potatoes, then mash them, put them in a bowl and add the eggs, cheese, breadcrumbs, salt and pepper. Mix all ingredients until smooth. Oil the bottom of an oven-proof dish and spread a 1cm layer of the potato mixture over the base of the dish, using wettened hands. Meanwhile fry the sliced onions until softened in plenty of olive oil, then add the olives, capers, fennel and tomatoes. Season with some salt. Cook for about twenty minutes then spread it over the potato mixture in the oven dish; finally finish by covering with another layer of the potato mixture, making sure your hands are kept wet. Sprinkle the breadcrumbs surface. Bake at 200 degrees centigrade for 25-30 minutes. Let it stand before you tuck in. This potato pie is even better the next day.