Magical Microwave Fudge

2 cups granulated sugar
2 cups firmly packed brown sugar
3/4 cup butter
1 cup canned evaporated milk
1 teaspoon vanilla extract
3/4 cup all-purpose flour
1 cup dark or milk chocolate chips and/or 1/2 cup
    peanut butter and/or 1/2 cup chopped nuts of choice

Mix first 5 ingredients together in large microwave-safe bowl. Microwave on HIGH for 15 minutes. Remove from microwave and quickly, while hot, beat in vanilla extract and flour. Add remaining ingredients. Mix well and quickly before the mixture cools. Pour into a well greased pan. Refrigerate.