Place dumplings in a (lightly greased) baking dish. Fry the onions and garlic in a little oil, add the ham, the stock and the chunky tomatoes, let the sauce boil through briefly. Season to taste with the specified spices and possibly thicken with the parmesan cheese.
Pour the sauce over the dumplings and place a slice of tomato and mozzarella on each dumpling. The whole thing can be sprinkled with parmesan or oregano.
Bake at approx. 190 ° C (convection) for 30-40 minutes.