For dip, in a medium saucepan combine cornstarch and brown sugar. Stir in apple cider, honey, lemon juice, cinnamon, salt (if desired), cloves, and allspice. Cook and stir until thickened and bubbly. Cook and stir for 2 minutes more. Remove from heat. Add butter or margarine; stir until melted. Serve dip warm with sliced apples. Makes 4 to 6 servings.