Cut the onion into cubes and chop the garlic. Halve the cherry tomatoes. Fry the meatballs with a little fat in a high saucepan, then add the onions and garlic and fry - but don`t let them burn.
Then add the cherry tomatoes and the canned tomatoes and let everything simmer together for about 20 minutes. Cut the basil into small strips and mix in. Finally, season the sauce with the spices to taste.
Put the spaghetti in a baking dish, pour the sauce over it and sprinkle with the grated cheese. Tear up the mozzarella and sprinkle it over the casserole as well.
Put the casserole in the oven preheated to 200 ° C and bake.