Cut the onion and fry it in heated oil. Add the mince and fry until ready, also adding the chopped tomatoes while frying. Season with salt and paprika. Add about 2/5 cup (100 ml) of warm water, sprinkle it with black pepper and cook until the liquid evaporates.
Cut the potatoes into small cubes and put them in a greased pan. Add the mince on top and top the moussaka with hot water, enough to cover the products. Bake in a preheated 356°F (180 °C) oven, for about 40 minutes.
Mix the products for the topping and pour them over the moussaka. Bake until reddened.