Preheat oven to 350°F. Grease a 24-cup mini muffin pan or line with paper liners.

In a microwave-safe bowl, combine the butter and semisweet chocolate chips. Microwave in 30-second intervals, stirring between each interval, until the mixture is smooth and melted.

In a large bowl, whisk together the melted chocolate mixture and granulated sugar until well combined.

Add the eggs one at a time, whisking well after each addition. Stir in the vanilla extract.

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

Gradually add the dry ingredients to the wet ingredients, stirring until just combined.

Using a small cookie scoop or tablespoon, drop the batter into the prepared mini muffin cups, filling each about 2/3 full.

Bake for 12-15 minutes, or until a toothpick inserted into the center of a brownie bite comes out with a few moist crumbs.

Remove the brownie bites from the oven and let them cool in the pan for 5 minutes before transferring them to a wire rack to cool completely.