Step 1

Sift sugar.

Step 2

Heat butter in a small pan on medium heat, do not let butter get brown.

Step 3

When butter is melted, whisk in cocoa, milk, and vanilla. Add sugar 1/2 cup at a time, whisking after each addition.

Step 4

Remove from heat, after all the sugar has been added.

Step 5

Whisk until smooth.

Step 6

Immediately pour over cake.

Step 7

If icing is too thin, add additional sifted sugar 1/4 cup at a time until desired thickness or sit it in the refrigerator a few minutes. Take it out and whisk it until creamy again.

Step 8

Frosting will thicken as it cools, but it'll be harder to spread.