Peanut Crunch Cake

1 package yellow cake mix

1 cup peanut butter

1/2 cup packed brown sugar

1 cup water

3 eggs

1/4 cup vegetable oil

1/2 to 3/4 cup semisweet chocolate chips, divided

1/2 to 3/4 cup peanut butter chips, divided

1/2 cup chopped peanuts (optional :-) )

In a mixing bowl, beat cake mix, peanut butter and brown sugar on low speed until crumbly. Set aside 1/2 cup. Add water, eggs and oil to remaining crumb mixture; blend on low until moistened. Beat on high for 2 minutes. Stir in 1/4 cup each of chocolate chips and peanut butter chips. Pour into a greased 9x13 baking pan. Combine peanuts, reserved crumb mixture and the remaining chips; sprinkle over batter. Bake at 350 degrees for 40 - 45 minutes or until a toothpick inserted near the center comes out clean. Cool completely.