Peel onions and cut them into rings. Cut the bacon into cubes. Wash meat and dab dry. Bring Brussels sprouts to the boil in salted water and cook over medium heat for 8-10 minutes. In the meantime, drain the bacon in a pan, remove and put aside.
Heat the oil in the pan and add the meat. Fry for 3-4 minutes on each side over medium heat. Add the onion rings 1-2 minutes before the end of the frying time. Meanwhile, bring 375 ml water and salt to the boil in a saucepan.
Remove from the heat and add cold milk. Stir in the puree flakes with a mixing spoon. Add butter and stir in. Flavour with nutmeg. Pour the Brussels sprouts into a sieve, drain.
Sprinkle the Brussels sprouts with bacon and arrange on plates with parsley, some frying fat, meat and onion rings as desired. Add puree to taste, sprinkled with parsley in a small bowl.