Preheat your oven to 350°F (175°C) and grease a 9x13 inch baking pan.
In a large bowl, mix the melted butter with brown sugar and granulated sugar until smooth.
Add in the eggs one at a time, mixing well after each addition.
Stir in the vanilla extract until fully incorporated.
In a separate bowl, whisk together the flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing just until combined.
Fold in the chocolate chips, ensuring even distribution.
Pour the batter into the prepared baking pan, spreading it evenly.
Bake for 20-25 minutes, or until a toothpick inserted comes out clean.
Allow to cool in the pan before cutting into squares and serving.