1
: Combine graham crumbs and butter; press evenly onto parchment-lined 13 x 9-inch (3.5 L) baking pan.
2
: Stir sweetened condensed milk, peanut butter and vanilla together. Pour evenly over crumb crust. Sprinkle with walnuts, followed by chocolate chips and peanut butter chips. Gently press into crust.
3
: Bake in preheated 350ºF (180ºC) oven 25-30 minutes or until lightly browned. Cool thoroughly and cut into bars. (Store loosely covered at room temperature.)