Beat shortening, peanut butter and sugars in large bowl with electric mixer on medium speed until light and fluffy.
Add egg and 2 teaspoons of the vanilla; mix well.
Gradually beat in flour, baking soda and salt on low speed until well mixed.
Stir in peanut butter chips.
Roll dough into a rectangle on a piece of greased parchment paper.
Place dough rectangle on top of brownies in pan.
(Alternative method: Drop cookie dough by tablespoonfuls on brownie, covering the top evenly.)
Bake 20 to 25 minutes longer or until cookie top is golden brown.
Cool in pan on wire rack.