FOR THE CHICKEN LIVERS: Remove any connective membranes. Salt and pepper to taste.
Saute chicken livers, apples, shallots and onions in butter over high heat until livers lose their pinkness. Heat cognac in a brandy warmer, ignite and carefully pour over the chicken livers. When flames die down, put this mixture into a blender container. Add sour cream and cream and blend at high speed until the livers are pureed and very smooth. Allow mixture to come to room temperature.
In your electric mixer, beat 3/4 cup butter until it is creamy. Beat in the cooled pate until it is thoroughly blended. Place mixture in a large crock or several small ramekins and refrigerate until firm.
When cold, baste with some melted butter. Serve with crackers, wafer thin black bread or thinly sliced cocktail rye bread.