Peel avocados and dice pulp. Puree pulp in blender container with chicken broth. Season to taste with salt and pepper. Gradually stir in whipping cream. Chill. Add cognac and sherry just before serving. Note: To make frozen avocado-shell cups for soup, cut a slice from stem end of avocado. Scoop out pulp and discard seed. Reserve cap. Use pulp for soup or puree with small amount of lemon juice and freeze for future use. Place shell upright in cup or egg carton. freeze until firm. To serve, embed avocado shell in crushed ice in a dessert dish or soup icer. Carefully spoon in soup and lean cap against side of avocado. Makes about 4 cups.