Preheat the oven to 325 degrees F.

Spray a 13x9 baking dish with cooking spray.

In a large bowl, cream together the peanut butter, butter, brown sugar and sugar until fluffy.

Add the eggs and vanilla extract and mix well.

In a small bowl, whisk the flour, baking powder and salt.

Gradually add the flour mixture to wet ingredients and mix well.

Spread the batter into prepared baking dish in an even layer.

Sprinkle the chocolate chips over the batter.

Bake for 5 minutes, remove and run a knife through the chocolate chips several times in any desired pattern.

Return to the oven and continue baking for 20-25 minutes or until a toothpick inserted in the center comes out clean. Under bake slightly for softer cookies, a little longer for crispy.

Remove to wire rack to cool.

Cut into squares and store in an airtight container until ready to serve.