This recipe recreates the nostalgic, creamy, and chewy treat from school cafeterias with a peanut butter and oatmeal base topped with rich chocolate buttercream frosting. It's a simple yet delicious dessert perfect for sharing, as it makes a whole sheet pan of bars.
Preheat oven to 350 degrees. Spray a (17 x 12 x 1 inch) baking sheet with non-stick spray. Set aside.
In a large bowl, cream the butter, sugar and brown sugar together with an electric mixer until combined and creamy.
Add peanut butter, eggs and vanilla extract. Cream together until combined.
Slowly fold in the flour, oats, baking powder and salt until all combined.
Spread cookie dough out in an even layer on the prepared baking sheet. The cookie dough is sticky so I use my hands to help spread and press the dough.
Bake at 350 degrees for 16 to 18 minutes. They will be nice and golden. Remove from oven and allow to cool completely.
FROSTING: Beat all frosting ingredients together with an electric mixer until smooth and creamy.
Spread frosting evenly on top of the cooled peanut butter bars. Cut into squares. Serves 24.