Cook the pasta in plenty of boiling salted water for 8-10 minutes. drain
Clean and wash the spinach, and chop it up roughly. Peel and chop the onion. Fry in hot oil. Add the spinach and let it collapse. Season with salt and pepper
Cut the sausage into fine strips. Mix with noodles and spinach and fill into a greased casserole dish. Dice the gorgonzola, grate the raclette, gouda and parmesan cheese
Heat the fat. Sweat flour in it. Deglaze with milk and stock. Boil up while stirring constantly. Melt half of the cheese in the sauce while stirring. Season to taste with a little salt and pepper
Pour the sauce over the casserole and sprinkle with the remaining cheese. Bake in the preheated oven (electric cooker: 200 °C/ circulating air: 175 °C / gas: level 3) for approx. 20 minutes. Garnish with herbs if necessary