Cook the spaetzle in salted water according to the instructions on the packet.
Cut the onion and bacon in cubes and the spring onions in rings. Briefly fry the bacon cubes in a pan, sauté the onion cubes and spring onion rings for about 5 minutes. Pour in the milk and melt the processed cheese in it. Season everything with salt and pepper and fold into the spaetzle. Put everything in a baking dish, sprinkle with cheese and bake in the preheated oven at 200 ° C (fan oven 180 ° C) on the middle rack for about 20 minutes.