01 - Set the oven to 350°F. Grease a 24-cup mini muffin tin or line with mini cupcake liners.
02 - In a medium bowl, whisk together the all-purpose flour, unsweetened cocoa powder, baking powder, and salt.
03 - In a large bowl, whisk the melted butter and granulated sugar until fully combined. Add eggs one at a time, whisking well after each addition. Stir in the vanilla extract.
04 - Fold the dry mixture into the wet ingredients until just combined, avoiding overmixing to maintain a tender texture.
05 - Gently fold in the semi-sweet chocolate chips or chunks to distribute evenly throughout the batter.
06 - Divide the batter evenly among the prepared mini muffin cups, filling each about three-quarters full.
07 - Bake for 12 to 15 minutes, or until the tops are set and a toothpick inserted into the center comes out with a few moist crumbs.
08 - Allow the brownie bites to cool in the tin for 10 minutes before transferring to a wire rack to cool completely.