Cut the liver, prepared as described above, into medium-thin slices or thin pieces. Peel the onions and cut them into thin rings.Put flour on a large plate and properly dust the liver pieces with it.
Heat 50 g of butter in a frying pan. Put the liver in the hot pan immediately after dusting it with flour. If you leave it lying longer, the flour coating becomes soft and does not adhere well.Fry the liver briefly from both sides and then cook it over moderate heat for about 10 to 15 minutes until done.
Take the liver out of the pan and keep it warm.
Now clean the apples and cut them into thin slices. Heat another tablespoon of butter in the same frying pan. We want to use all these great roasting flavours!First soften the apple slices until slightly brown. Take them out.
Now add the onion rings and simmer until golden brown. While the onions are browning, sprinkle with a little salt.When the onions are fninshed, you can now lightly salt the liver from both sides.
Put liver slices on plates and arrange apple slices and onions on top.
Notes
How to perfectly brown onions: Always brown onions on low heat, that will bring out the finest taste. That´s because no bitter substances are released this way. Leave them at low heat until they are soft.