Cut the potatoes into cubes, also cut the meat into cubes and transfer all of it to an ovenproof baking dish. Add the chopped onion, the salt, the black pepper, the sweet paprika and the olive oil, mix it all together very well.
Cover the baking dish with aluminum foil and bake in a preheated oven at 200°C (392°F) for 40 to 50 minutes.
After this indicated baking time, take it out of the oven, remove the foil and top it with the shredded mozzarella cheese and oregano to taste. Take it back to the oven for another 15 minutes, just to melt the cheese.
Serve.