Want to take your brownies to the next level? It's easy! You'll need just four ingredients and 5 minutes to produce a creamy, rich, delicious chocolate brownie icing.
Sift the icing sugar and cocoa powder into a bowl.
Add cubed butter and 2 teaspoon of milk.
Whisk slowly until it starts to clump, then speed up and whip until the frosting is light and creamy. If it seems too thick, you can whisk in more milk, a few drops at a time.
To use, spread thickly onto chilled brownies before slicing.
Notes
This should make enough frosting to spread on top of a full medium tray of brownies (e.g. any of my full batch brownie recipes).