Clean, wash and quarter the cabbage and cut into strips from the stalk. Peel and finely chop the onions. Heat the oil in a large pot. Fry half of the onions in it until transparent. Add the cabbage and steam for about 5 minutes.
Season with salt, pepper and caraway. Add 1/4 l water and 1 teaspoon broth, bring to the boil, cover and stew for 5 minutes.
Cook the spaetzle in boiling salted water for about 16 minutes (see also package instructions) until firm to the bite. Drain the cabbage and collect the cooking liquid. Measure out 1/4 l and fill up with water if necessary.
Heat 3 tablespoons of fat in a saucepan. Fry the remaining onions until translucent. Stir in flour and sweat. Stir in milk, cream and cooking stock. Bring to the boil, stir in 1 tsp. stock and simmer for approx. 5 minutes.
Stir in mustard and season the sauce with salt, pepper and lemon juice.
Drain the spaetzle, rinse with cold water and drain. Mix with the cabbage and put into a large greased casserole dish. Pour mustard sauce over it. Cover with bacon. Bake in the preheated oven (electric cooker: 200 °C/circulating air: 175 °C/gas: level 3) for 30-40 minutes.
Sprinkle roasted onions over it about 10 minutes before the end of the baking time.
Drink tip: red wine, e.g. a Spätburgunder.