Preheat oven to 350°F. Spray a 9x13 pan with cooking spray.
Cream together butter and both sugars.
Beat in eggs.
Mix in vanilla, baking powder, and salt.
Slowly stir in flour, mixing until combined.
Spread 2/3 of the batter in the bottom of the pan. It will be sticky and it won't seem like enough, but it will be! To help spread it, you can spray your hands with the cooking spray and press it down in the pan.
Combine filling in a small bowl, sprinkle evenly over bottom layer.
Drop the remaining dough over the top. It won't cover it all the way, but that's okay. Drop some here. Drop some there. Drop it like it's hot.
Bake for about 20-25 minutes until a toothpick comes out clean from the center.
Once cooled a bit, cut into bars.
Eat alone or topped with vanilla ice cream!
Notes
To freeze: Once it cools completely, cut into bars, wrap each bar in plastic wrap and store in a freezer safe container. Defrost before eating by letting them sit out on the counter or microwave for a few seconds.