Preheat your oven to 350°F (175°C). Grease a mini muffin tin or line it with mini muffin liners.

Melt the butter in a medium saucepan over low heat. Stir in granulated sugar until combined and smooth.

Incorporate the eggs one at a time, beating well after each addition. Add vanilla extract and mix thoroughly.

In a separate bowl, whisk together cocoa powder, flour, salt, and baking powder.

Combine dry ingredients with wet mixture gradually, stirring gently until just mixed. Fold in chocolate chips if using.

Spoon the batter into the mini muffin tin, filling each cup about 2/3 full.

Bake for 15–20 minutes until a toothpick comes out with a few moist crumbs.

Cool in the pan for about 5 minutes, then transfer to a wire rack to cool completely.

Serve as is or dust with powdered sugar if desired.