Chocolate Butter Cream Icing

So this is just a bit different from the regular vanilla butter cream recipe that I posted a while back, but it's still very simple. By the way I made some back at Christmas for a family party and to be honest it tastes like Hershey's kisses.
Ingredients:
5 cups powdered sugar
1/2 cup unsweetened cocoa powder
1 cup butter (2 sticks softened real butter)
Heavy whipping cream
1 teaspoon vanilla extract
Steps:
First whip both sticks of butter in an electric mixer until its creamed. Next add in the half cup of cocoa powder until it is completely combined with the butter. Then slowly add in, a half cup at a time, the powdered sugar. Don't worry if it starts to get crumbly once you add in the heavy whipping cream it will smooth back out. Once all the powdered sugar is added in then add 1 teaspoon of vanilla and your heavy whipping cream. Only add in the heavy whipping cream 1 tablespoon at a time because if you add to much then you won't have the fluffy consistency that you're wanting.