Chocolate chip cookie bars are soft, chewy, and easier than making traditional cookies. Skip the process of chilling the dough and forming it into balls - and bake your cookie dough in a 9x13 inch pan instead.
Line a 9x13 inch pan with parchment paper leaving an overhang around the sides. Or line with aluminum foil and lightly spray with cooking spray.
In a medium bowl whisk together the flour, cornstarch, baking powder and salt.
In a large bowl whisk together the melted butter and sugars (or use an electric mixer).
Whisk/beat in the eggs, egg yolks and vanilla extract.
Stir (or beat) in the flour mixture about ½ at a time.
Fold in the chocolate chips using a rubber spatula or wooden spoon.
Spoon the batter into the lined pan and spread the top smooth.
Bake in the preheated oven for 32-37 minutes, or until the top looks set.* Baking for longer will lead to less gooey/chewy bars.
Cool fully before cutting for clean slices, or cool for at least 30 minutes before slicing.
*Baking in a ceramic or glass pan generally means the bars will bake for 3-5 minutes longer.This recipe can be easily halved and baked in an 8x8 or 9x9 inch pan. The bake time will be about the same, or a little shorter. Store in an airtight container at room temperature for up to 4 days. Bars freeze well and can be thawed in the fridge.