01 - Preheat the oven to 350°F. Grease a mini muffin tin or line with mini paper cups.
02 - In a medium bowl, whisk together melted butter and sugar until combined. Stir in eggs and vanilla extract.
03 - Add cocoa powder, flour, salt, and baking powder. Mix until just combined; do not overmix.
04 - Scoop the batter evenly into the prepared mini muffin tin, filling each cavity about 2/3 full.
05 - Bake for 13–15 minutes, or until a toothpick inserted into the center comes out with a few moist crumbs.
06 - Let brownie bites cool in the tin for 5 minutes, then transfer to a wire rack to cool completely.
07 - In a small bowl, whisk together powdered sugar, milk, and vanilla extract to form a smooth glaze.
08 - Drizzle the glaze over cooled brownie bites. Immediately top with red and blue sprinkles. Garnish with fresh blueberries and diced strawberries, if desired.
09 - Allow glaze to set before serving.