Once butter is melted, stir in cocoa and mix until butter and cocoa have combined.
Next, using an electric mixer, alternately add powdered sugar and cream, beating until light and fluffy. Add in vanilla and mix well.
Add an extra teaspoon of cream if a thinner consistency is desired. If frosting seems too thin, add additional powdered sugar, one tablespoon at a time until desired consistency is reached.
Spread or pipe onto cakes or cupcakes as desired.