Cut the liver into strips and dust with flour. Cut the onions and mushrooms into strips.
Then fry the liver in a pan with a little margarine. Then add the onions and mushrooms and fry with them.
Deglaze with sherry and top up with cream. Cut the sage leaves into small pieces and add them. Then simmer for about 15 minutes. Season to taste with salt and pepper. Mashed potatoes are best served with this.