1Heat oven to 350 Spray a 9" x 13" baking pan w/ cooking spray. In lg bowl make cake as directed on pkg.
2Stir in dark chocolate chips and 1 cup peanut butter pieces. Pour batter into pan. Bake 30-33 min, or until toothpick inserted in center comes out clean. Let cool 10 min. Poke holes in top of cake w/ small wooden handle.
3Pour condensed milk over holes in cake. Pour 1 cup chocolate syrup over holes in cake. Let cool completely. Top cake w/ whipped topping. Drizzle w/ remaining chocolate syrup. Drizzle w/ peanut butter topping and sprinkle w/ remaining peanut butter pieces.