Peel the potatoes and cook in salted water for about 20 minutes. For the meatballs soak the rolls. Peel and finely dice the onions. Heat 1 tablespoon of oil in a frying pan. Fry half of the onions in it until transparent. Take them out. Knead minced meat, squeezed bread roll, egg, mustard and steamed onions. Season with salt and pepper. Form small balls from the mixture with moistened hands. Heat 2 tablespoons of oil in a large frying pan. Fry the meatballs in it all around for about 5 minutes until golden brown.
For the sauce in the meantime clean, wash and halve the mushrooms. Take the meatballs out of the pan. Sauté the mushrooms in the frying fat. Add the remaining onions and fry for about 2 minutes. Deglaze with 400 ml water. Stir in cream cheese, bring to the boil and simmer for about 3 minutes. Season sauce with salt and pepper. Add meatballs to the sauce. Wash and finely chop the chives and stir into the sauce.
For the puree, drain the potatoes. Add milk and butter, mash everything finely. Season to taste with salt and nutmeg. Arrange meatballs with cranberries. Serve with mashed potatoes.