Melt the butter in a large skillet. Add the onions and sauté until tender. Add the chicken livers, salt, mustard, nutmeg, and cloves. Cover and cook over low heat for 10 to 15 minutes or until livers are cooked through and all pink has disappeared. Place in food processor with steel blade and process until smooth.
While processor is running, add the cream cheese, 2 ounces at a time through the feed tube. When well blended, add the Cognac and continue running the processor until it is well blended. Pour the mixture onto a pate tureen or a soufflé dish. Refrigerate 18 to 24 hours before serving.
Makes 16 servings