Caramel Layer Chocolate Bars
["1 small can evaporated milk, divided", "14 oz. pkg. light caramels", "1 pkg. (17 to 18 oz.) German or Swiss chocolate cake mix", "3/4 c. melted margarine", "1 c. chopped nuts", "6 oz. pkg. semi-sweet chocolate pieces"]
["Grease and flour a 13 x 9-inch baking pan.", "Combine 1/3 cup evaporated milk and caramels (50) in top of double boiler. Cook over", "hot", "water, stirring often, until caramels melt and mixture is smooth.\tSet aside."]
["milk", "light caramels", "margarine", "nuts", "semi-sweet chocolate pieces"]