Prepare the spaetzle according to the instructions on the packet.
In the meantime, dice the bacon. Brush, clean and thinly slice the mushrooms.
Put the bacon cubes in a non-stick pan in hot oil over medium heat. Fry the mushrooms in it over high heat while stirring. Season with salt and pepper. Stir the sour cream into the mushrooms and pour in the milk. Boil everything down creamy in a few minutes over medium heat. Wash and finely chop the parsley.
Drain the spaetzle, mix in the mushroom pan and sprinkle with parsley.