Whisk or sift all dry ingredients (2 cups all-purpose flour, 1 3/4 tsp baking powder, 3/4 tsp saltin a small mixing bowl.
In large mixing bowl, cream 1/2 cup unsalted butter, softened, 1 1/2 cups granulated sugar and 3/4 cup brown sugar until light and fluffy, about 2 minutes.
Add in 3 large eggs, one at a time followed by 1/2 cup crunchy peanut butter and 1 1/2 tsp vanilla extract
Add dry ingredients, mix only until combined. Fold in 1/4 cup finely chopped peanuts
Spread in greased 15"x10" jelly roll pan and bake at 350°F for 20-25 minutes, or until a toothpick comes out clean when inserted into center of pan.
Cool pan on wire rack completely before cutting into bars.
Notes
Store baked bar cookies in an airtight container up to 72 hours
Freeze baked bar cookies in an airtight container up to 45 days
This recipe has not been tested with natural peanut butter