This originally came from "Taste of Home" magazine, which, if you don't mind excessive nostalgia and the annoying presence of Midwestern nuclear families, is a pretty damn good source of recipes.

1/2 cup softened butter or margarine
1/2 cup packed brown sugar
2 tablespoons milk
1/2 teaspoon baking powder
1/4 cup creamy peanut butter
1/3 cup baking cocoa
2/3 cup sugar
2 eggs
3/4 cup all-purpose flour
1/4 teaspoon salt
1/3 cup peanut butter chips
1/2 cup chocolate chips

  1. Cream butter and sugars. Add eggs and milk; mix well.

  2. Combine flour, baking powder and salt; add to sugar mixture and mix well.

  3. Divide batter in half. To one half, add peanut butter and peanut butter chips and mix well. To the other half, add the cocoa and the the chocolate chips and mix well.

  4. In a greased 9" square baking pan, spoon the chocolate batter in 8 mounds in a checkerboard pattern. Spoon seven mounds of the peanut batter in between the chocolate batter. Swirl the two batters together with a knife.

  5. Bake at 350 degrees Fahrenheit for 25 to 30 minutes.