Microwave Directions: Combine sugar, water, butter and corn syrup in 2-quart casserole. Microwave, stirring after half the time,3 1/2 - 4 1/2 minutes or until mixture comes to a full boil. Boil 2 minutes. Immediately add chocolate chips; beat with wire whisk or rotary beater until smooth. Stir in vanilla. Serve warm over ice cream or cake.