Preheat Your Oven: Preheat your oven to 350°F (175°C). Grease a 9x13-inch baking dish or line it with parchment paper for easy removal.
Combine Wet Ingredients: In a large mixing bowl, whisk together the melted butter and granulated sugar until well blended. Add the eggs, one at a time, mixing well after each addition, and then stir in the vanilla extract.
Mix Dry Ingredients: In a separate bowl, combine the flour, baking powder, and salt. Gradually add the dry mixture to the wet mixture, stirring until just combined.
Fold in Chocolate Chips: Gently fold in the chocolate chips, making sure they are evenly distributed throughout the batter.
Pour into Prepared Dish: Pour the batter into the prepared baking dish, spreading it evenly with a spatula.
Bake: Bake in the preheated oven for 25-30 minutes or until the edges are golden brown. The center may look slightly underbaked; that's the gooeyness we're after!
Cool and Serve: Allow the bars to cool in the pan for about 10 minutes before transferring them to a wire rack to cool completely. Cut into squares and enjoy!