Melt 3 tablespoons butter in heavy skillet over medium heat. Add onions and cook until soft, about 5 minutes. Add apple and cook until soft, about 4 minutes depending on how big pieces are. Transfer mixture to food processor or blender.
Note: Don’t wash skillet after cooking onion-apple mix. Leftover bits add flavor.
Melt 1 tablespoon butter in skillet, add livers and cook until well browned, about 10 minutes. Add livers to onion mixture, followed by wine, and boil over high heat until reduced by half, which should take a few minutes. Scrape from bottom any browned bits in skillet and transfer pan contents into the onionapple mix. Add cream and purée until smooth. Let cool about 10 minutes, until warm.
Add remaining butter (which should be a little soft by now) 1 tablespoon at a time, stirring it into the liver mixture. After all butter is added, add lemon juice, cayenne and season to taste with salt and pepper.
Divide pâté into individual ramekins or smooth into an attractive serving dish. Refrigerate until well chilled. Pâté freezes well and keeps refrigerated about a week.