Peel the onion and cut into small cubes. Cut the mushrooms into slices, finely chop the parsley.
Fry the sausage until it is nice and brown. Then cut into small pieces and return to the pan with the onion cubes and continue to fry. Add the mushrooms and stir-fry for 5 minutes. Then fill up with 500 ml of water and stir in the gravy. Finally stir the parsley into the sausage goulash.
Cook the spaetzle in plenty of salted water, serve with the goulash,