Preheat your oven to 350°F (175°C).
In a large mixing bowl, cream the unsalted butter and granulated sugar together until light and fluffy.
Add the eggs, one at a time, and blend until fully incorporated, then stir in the vanilla extract.
In a separate bowl, whisk together the flour, cocoa powder, baking powder, and salt.
Gradually add the dry ingredients to the wet mixture, mixing until just combined.
Fold in the chocolate chips, if using.
Scoop tablespoon-sized portions of dough onto a parchment-lined baking sheet, leaving space between them.
Bake in the preheated oven for 10-12 minutes until the edges are set but the centers still look slightly soft.
Allow the cookies to cool on the baking sheet for 5 minutes before transferring to a wire rack.
Enjoy your meltaway brownie cookies warm or allow to cool completely.