Preheat your oven to 180°C (350°F).

In a mixing bowl, add the softened butter, brown sugar, and white sugar. Use an electric mixer or a whisk to beat until light and fluffy.

Crack the egg into the bowl and add the vanilla extract. Mix until well combined.

In another bowl, mix the flour, cocoa powder, baking powder, baking soda, and salt. Sift to remove lumps.

Gradually add the dry mixture to the wet mixture. Stir gently until just combined; avoid overmixing.

Fold in the chocolate chips or chunks until evenly distributed.

Use a cookie scoop or tablespoon to drop dough onto the baking sheet, leaving space between cookies.

Bake for about 10-12 minutes, until edges are set and centers look slightly underbaked.

Allow cookies to cool on the baking sheet for 5 minutes before transferring to a cooling rack.