Prepare Maultaschen in boiling salted water according to package instructions. Clean and quarter the mushrooms. Clean, wash and cut leek into strips. Cut bacon into strips. Heat 1 tablespoon of fat in a pan and fry the bacon for about 1 minute.
Add the mushrooms and leek and fry briefly.
Wash the parsley, shake dry and pluck the leaves from the stalks. Drain Maultaschen, arrange on plates and serve with the Gröstl. Garnish with parsley. Apple compote tastes good with it.