Eggs on a Dish, Fermiere

Cut the gall from one chicken liver, mince the latter and put it into a pan with butter and a spoonful of chopped onions; season and cook, but not too quickly, while turning over; remove the liver with a skimmer and put one spoonful of chopped-up mushrooms into the pan; let the moisture reduce. Place this in the bottom of an egg dish, on this the liver, break two eggs over, season, pour over some melted butter and cook in the oven.