Clean, wash and cut the savoy cabbage into 8 slices. Heat the oil in a large pan. Brown the cabbage in it. Pour in broth and braise covered for about 12 minutes. Bring 1/2 litre of water to the boil in a saucepan.
Remove the pot from the stove, let the water cool down for 1 minute. Stir in the puree flakes briefly with a wooden spoon. Cover and set aside. Peel onions and cut into rings. Rinse liver and pat dry.
Turn liver in flour, shake off excess flour. Heat clarified butter in a pan. Fry the liver for 2-3 minutes on each side. Season with salt and pepper, remove and keep warm.
Put onion rings in the frying fat and fry until golden brown. Lift the savoy cabbage slices out of the water and let them drip off a little. Arrange mashed potatoes, savoy cabbage, liver and onions on plates. Sprinkle with pepper.