1. Preheat your oven to 350°F (175°C) and grease a 9×13 inch baking dish with butter or non-stick spray.
2. In a large saucepan, melt the butter over low heat. Remove from heat and stir in the sugar, followed by the eggs one at a time, ensuring each is fully incorporated.
3. Add the vanilla extract and mix well. I always find this step reminiscent of the vanilla aroma that filled our kitchen during my childhood.
4. In a separate bowl, combine the flour, cocoa powder, salt, and baking powder. Gradually add this to the butter mixture, stirring until just combined.
5. Fold in the chocolate chips, letting them melt slightly into the batter for an extra fudgy texture.
6. Pour the batter into the prepared baking dish, spreading it evenly with a spatula.
7. Bake for 30-35 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs. Avoid overbaking to maintain that fudgy center.
8. Allow the cake to cool in the pan before slicing into squares and serving. Enjoy it warm for the ultimate gooey experience.

Remember, patience is key, just like my abuela taught me. Letting the cake cool slightly ensures you get those perfect slices.