Preheat oven to 350°F and grease a 9×9-inch baking pan with nonstick spray.
In a medium bowl, stir together melted butter, brown sugar, vanilla, and egg until well combined.
Add flour, baking powder, salt, and baking soda and stir to combine.
Stir in chocolate chips and pour into prepared pan. Bake 20-25 minutes. Enjoy!
