For the potato pancakes, squeeze the liquid out of the peeled & grated potatoes and combine them with the eggs, flour, salt, pepper, and nutmeg.
For the ground beef mixture, combine the ground beef, eggs, bread crumbs, bell pepper, parsley, mozzarella cheese cubes, salt, and pepper.
Heat some cooking oil in a 6-inch frying pan over low heat. Add about 3-4 large spoonfuls of the potato pancake mixture to the pan and evenly spread it out. Add about 1 tablespoon of water to the pan and cover the pan with a lid. After 3-5 minutes, remove the lid, let the remaining water evaporate, and remove the pan from the heat.
Spread some of the ground beef mixture over one side of the potato pancake and flip the other side over it. Remove the potato pancake omelet from the pan and let cool. Repeat the process until you have 12 potato pancake omelets.
Grease a 10-inch springform pan and arrange the potato pancake omelets in a circle inside the pan (with the open ends facing down), working from the outer walls in towards the center. Sprinkle the shredded mozzarella cheese in the gaps, transfer the pan to a preheated oven, and cook at 350°F for 45 minutes.