1/3 c. butter
1/2 c. sugar
1/2 c. firmly packed brown sugar
2 eggs
1/2 c. smooth or crunchy peanut butter
1 c. self-rising flour
1/2 tsp. vanilla
1 pkg. (6 oz.) semi-sweet chocolate pieces

Preheat oven to 350 degrees. Grease bottom of 9 inch square baking pan.

Melt butter in saucepan over low heat. Remove from heat. Stir in remaining ingredients in order listed; mix well. Spread in prepared pan. Bake 30 to 35 minutes. Cool in pan. Cut into 16 squares.