Rinse the potatoes, place in a pan, cover with cold water and bring to the boil. Once cooked, drain and peel while still warm. Mash them immediately. Cut the mozzarella, the salame and the slice of ham in 1cm cubes and set aside. Add the eggs and the parmesan to the mashed potatoes, and season to taste. Mix in the diced ingredients, oil a 20 × 20 cm square baking dish and sprinkle with breadcrumbs. Pour the mixture with the help of a spatula to level it. Sprinkle the surface with breadcrumbs and Parmesan cheese, season again with a drizzle of oil and bake in a preheated static oven at 180 °C for about 30 minutes. Once cooked your potato gateau will be steaming hot and ready to be served.