2/3      C granulated sugar
1/2      C packed brown sugar
1/2      C butter or margarine - softened
2         tbsp. milk
2         eggs
3/4      C all-purpose flour
1/2      tsp. baking powder
1/4      tsp. salt
1/4      C creamy peanut butter
1/3      C peanut butter cocoa
1/3      C semisweet chocolate chips

Heat oven to 350 degrees. Grease square pan, 9 x 9 x 2 inches. Beat sugars,
butter, milk and eggs in large bowl with electric mixer on medium
speed, or mix with spoon. Stir in flour, baking powder and salt. Divide
batter in half (about 1 cup plus 2 tablespoons for each half). Stir
peanut butter and peanut butter chips into one half. Stir cocoa and
chocolate chips into remaining half.

Spoon chocolate batter into pan in 8 mounds in checkerboard pattern.
Spoon peanut butter batter between mounds of chocolate batter.
Gently swirl through batters with knife for marbled design.

Bake 30 to 35 minutes or until toothpick inserted in center comes out
clean. Cool completely. Cut into 4 rows by 4 rows.