Peel, wash and cut the potatoes into pieces. Cook in boiling salted water for about 20 minutes. Cut the bacon into strips and leave them crispy in a pan without fat. Take out and drain on kitchen paper.
Clean and clean the mushrooms and cut them into slices. Peel and roughly dice the onions. Heat 2 tablespoons of oil in the bacon fat. Fry the mushrooms for 6-8 minutes while turning. After about 3 minutes add onions. Drain the potatoes and let them evaporate briefly.
Add 100 ml milk and 1 tablespoon butter, crush everything. Season to taste with salt and nutmeg, leave to cool.
Melt 1 tablespoon of butter in a saucepan. Stir in the flour, sweat briefly. Gradually add 100 ml milk and stock while stirring. Stir in mustard. Bring to the boil, simmer for 6-8 minutes, remove from heat.
Add mushrooms, onions and bacon.
Clean the pointed cabbage, quarter it and cut out the stalk. Cut cabbage into strips. Mix the egg with the potato mixture. Cut off with 2 tablespoons of dumplings. Heat water in a pot and put a sieve insert in it.
Steam the gnocchi for about 10 minutes with the lid closed. Heat 1 tablespoon of oil in a frying pan and sauté the pointed cabbage for 5-8 minutes. Wash chives, shake dry and chop finely. Arrange potato dumplings with sauce and pointed cabbage, sprinkle with chives and serve immediately.