1 yellow cake mix
1/2 c. packed brown sugar
1 c. creamy peanut butter
1 c. water
1/4 c. vegetable oil
3 eggs
1 c. semi-sweet chocolate chips
1/3 c. chopped nuts (optional)

Heat oven to 350 degrees. Grease and flour 13 x 9 x 2 inch pan. Beat cake mix, brown sugar, and peanut butter in large bowl on low speed until crumbly. Set aside 2/3 cup of the crumbly mixture. Beat remaining crumbly mixture, the water, oil and eggs on low speed, scraping bowl constantly until moistened. Beat on medium speed, scraping bowl frequently for 2 minutes. Pour batter into pan. Stir the optional nuts into the reserved crumbly mixture. Spoon over batter. Sprinkle the chocolate chips. Bake until cake springs back when touched lightly in center, approximately 40-45 minutes.