Reese's Peanut Butter Oatmeal Cookie Bars

1 1/2 sticks unsalted butter
2 cups light brown sugar
1/2 cup creamy peanut butter
2 eggs, room temperature
1 tbsp. vanilla
2 cups flour
1 cup ond-fashioned oats
2 1/2 tsp. baking powder
1/4 tsp. salt
1 cup Reese's peanut butter baking chips
2 cups chopped Reese's peanut butter cups

1.  Preheat oven to 350 degrees.  Line a 9x13 baking dish with foil.  Spray with cooking spray and set aside. 
2.  Cream butter and sugar together in a large mixing bowl.  Add peanut butter and continue mixing.  Add eggs, one at a time, beating well after each addition.  Stir in vanilla.
3.  In a separate bowl, combine the flour, oats baking powder, and salt.  Slowing add this mixture to the butter mixture, stirring until combined.
4. Mix in the peanut butter chips.
5.  Press 2/3 of the dough into the prepared pan, fully covering the bottom of the pan.  Sprinkle with chopped Reese's.  Drop remaining dough in small pieces over the Reese's (you won't be able to cover all of th Reese's, but this doesn't matter).
6.  Bake for 25-30 minutes, until lightly browned and cooked through.  Allow to cool completely before cutting into squares.