Peanut Crunch Cake

1 (18.25 ounce) box 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

Heat oven to 350 degrees F.

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 chocolate and peanut butter chips. Pour into a greased 13 x 9-inch baking pan.

Combine peanuts, reserved crumb mixture and the remaining chips; sprinkle over batter. Bake for 40 to 45 minutes or until a wooden pick inserted near the center comes out clean. Cool completely.

Yields 12 to 16 servings.