Peanut Butter Fudge

2/3 cup butter
2/3 cup peanut butter (chunky or smooth)
6 cups confectioners' sugar
1/3 cup milk
1 tablespoon vanilla extract

In a large microwave safe bowl place butter and peanut butter. Microwave on HIGH until butter melts (1 1/2 to 2 minutes); stir until well blended.

Add remaining ingredients; stir until lumps of sugar disappear. Microwave on HIGH until soft but not bubbly (1 to 1 1/2 minutes); stir. Pour into buttered 9-inch square baking pan. Cover; refrigerate at least 1 hour.

Cut into 1 1/2-inch pieces. Store in refrigerator.

If desired, spread chocolate frosting after fudge is chilled.