Preheat oven to 350° and line a 9×9 inch or 13 x 9 x 2-inch pan with foil. Bring foil side up and over the pan. You will use the foil “handles” to lift the lemon bars from the pan after baking. Spray foil with pan release, or butter and flour.
In a medium sized mixing bowl, add flour and powdered sugar. Mix on low for 1 minute to combine.
Add softened butter to flour mixture and mix on medium until mixture resembles coarse sand.
Add shortbread dough to the baking pan. Press firmly and evenly into the pan.
Bake for 20-25 minutes until the crust is lightly browned.