Line a 24-count mini muffin tin with liners and grease generously. Preheat the oven to 180C/350F.
In a microwave safe bowl, add the butter and chocolate and microwave for 20-30 seconds, until the chocolate has melted. Whisk into the butter until smooth.
Add the sugar, followed by the eggs, one at a time, until fully incorporated. Add the cocoa powder and mix until a thick brownie batter remains.
Evenly distribute the batter amongst 20-24 of the greased mini muffin tins.
Bake for 12-15 minutes, or until crackly on top.
Let the brownie bites cool in the pan completely, before enjoying.
Notes
TO STORE: Place these brownies in an airtight container or bag and store them at room temperature for up to 3 days. Refrigerating the brownies will make them last as long as a week. TO FREEZE: If you have made a bigger batch of these bite-size brownies, transfer them to a freezer bag, push out the excess air, and freeze them for up to 3 months. For the best results, wrap each brownie with food wrap.