peanut butter chocolate chip cookie bars

I needed a treat to take to someone after church today and knew I wanted to use up the rest of a jar of peanut butter.  It turns out this recipe is GREAT!

peanut butter chocolate chip cookie bars (adapted from spend with pennies)
1 cup unsalted butter, softened
1 cup peanut butter
1 1/2 cups light brown sugar
1/2 cup sugar
1 large egg plus 1 large egg yolk
2 teaspoons vanilla extract
2 3/4 cup flour
1 teaspoon cornstarch
1/2 teaspoon baking powder
1/4 teaspoon salt
2 tablespoons milk
2 cups chocolate chips

Preheat oven to 350 degrees and line a 9x11 pan with wax paper.
Using an electric mixer, cream together butter, peanut butter and sugars.  Add eggs and vanilla extract.  Add flour, cornstarch, baking powder and salt.  Add milk and incorporate.  Fold in chocolate chips.  Transfer batter to the prepared pan and spread evenly.
Bake for 35 minutes or until edges are beginning to turn golden brown and a toothpick comes out clean.