Amazing Microwave Fudge

2 cups granulated sugar
2 cups brown sugar, packed
3/4 cup butter
1 cup evaporated milk
1 teaspoon vanilla extract
3/4 cup all-purpose flour
1 cup semisweet or milk chocolate chips
1/2 cup peanut butter
1/2 cup chopped nuts (optional)
Line bottom and sides a 9-inch square baking pan with lightly buttered waxed paper or aluminum foil. Set aside.
Mix first 5 ingredients together in large microwave safe bowl. Microwave on HIGH for 15 minutes.
Remove from microwave oven and quickly beat in vanilla and flour. Stir in chocolate chips, peanut butter and nuts, stirring until chocolate has melted and mixture is blended well. Allow to cool at room temperature to firm.
Lift from pan; peel away waxed paper and cut into squares.
Makes about 1 1/2 pounds fudge.