Preheat your oven to 350°F (175°C). Grease a baking pan.
In a mixing bowl, combine melted butter, brown sugar, and granulated sugar.
Add eggs and vanilla extract, and mix well.
In another bowl, whisk together flour, baking powder, and salt.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined.
Fold in the chocolate chips.
Spread the batter evenly in the prepared baking pan.
Bake for 25 minutes or until a toothpick inserted into the center comes out clean.
Allow to cool before cutting into squares.