Clean, peel and wash the potatoes, carrots, Brussels sprouts and paprika into bite-sized pieces. Then cook in salted water until firm to the bite for about 5-10 minutes depending on the type of vegetable.
Clean the fennel and cut into strips. Halve meatballs fresh or from the day before, depending on size. Peel the onion and cut into small cubes.
Preheat the oven to 180 ° C.
Sweat the onion cubes in a little oil, add meatballs and fry with them. Then put in a baking dish. Drain the vegetables, possibly use the cooking water for the sauce. Also put the vegetables in the baking dish and distribute them.
Fry the fennel in a little oil, sprinkle with cornstarch and deglaze with cream and a little milk, add some of the cooking water if necessary. Season with salt, pepper and nutmeg. Melt half of the grated cheese in the sauce while stirring.
Pour the sauce over the vegetables in the baking dish. Scatter the rest of the grated cheese on top. Then bake in the preheated oven for about 35-40 minutes.
Serve the casserole garnished with fresh herbs.