Preheat your oven to 350°F (175°C) and grease a baking pan.
In a mixing bowl, whisk together the flour, cocoa powder, baking powder, and salt.
In a separate bowl, combine the sugar, melted butter, eggs, vanilla extract, and brewed espresso. Whisk until well blended.
Gradually add the dry ingredients to the wet mixture, stirring until just combined.
Fold in the chopped dark chocolate, ensuring it is evenly distributed throughout the batter.
Pour the batter into the greased baking pan, spreading it out evenly.
Bake in the preheated oven for 25-30 minutes or until a toothpick inserted in the center comes out with a few moist crumbs.
Remove from the oven and let the brownies cool in the pan before cutting into squares.
Indulge in the delectable espresso brownies, savoring each rich and fudgy bite.