1/3 c. butter, melted
1/2 c. sugar
1/2 c. firmly packed brown sugar
1/2 c. chunky peanut butter
1/2 tsp. vanilla
1 egg, beaten
1/4 c. milk
1 1/2 c. flour
1/2 tsp. baking soda
1/2 tsp. salt
1 pkg. (6 oz.) semi-sweet chocolate chips

Combine first 7 ingredients and mix well. Combine flour, soda and salt. Add dry ingredients and chocolate chips to peanut butter mixture, stirring well. Pour batter into a greased 9 inch square pan. Bake at 375 degrees for 25 minutes. Cool completely and cut into squares.