This frosting is so smooth and creamy, you might not use it on just brownies!
unsweetened cocoa powder
(125g) confectioners sugar
or heavy cream
In a stand mixer with the whisk attachment (a hand mixer works excellently here), combine room temperature butter, cocoa, honey, vanilla, and confectioners sugar.
Turn mixer on low and let it combine ingredients for about 30 seconds.
Slowly add milk, one tablespoon at a time, until you reach desired consistency. You may not need all 3 tablespoons, you may need 1 more, it can vary from season to season and kitchen to kitchen.
Spread over warm brownies.