Prepare brownie batter according to package directions; stir in peanut butter chips before baking.
Bake in a greased 13inch x 9inch baking pan at 350 degrees for 20-25 minutes or until a toothpick insered near center comes out with moist crumbs. DO NOT OVERBAKE
Cool on a wire rack; cut into 3/4 inch pieces.
Cut peanut butter cups in half; set aside 1/3 cup for garnish.
In a large bowl, whisk milk and pudding mixes for 2 minutes or until soft-set.
Add peanut butter and vanilla to pudding and mix well. Fold in 1-1/2 cartons whipped topping.
Place a third of the brownies in a 5 quart glass bowl; top with a third of the remaining peanut butter cups. Spoon a third of the pudding mixture over top. Repeat layers twice. Cover with remaining whipped topping; garnish with reserved peanut butter cups.