Prepare the Butter
In a large mixing bowl, beat the softened butter on medium speed for 1-2 minutes, until it’s creamy and smooth.
Add the Cocoa Powder and Sugar
Sift together the powdered sugar and cocoa powder to remove any lumps. Gradually add the sugar-cocoa mixture to the butter, beating on low speed after each addition to prevent a sugar cloud.
Add the Cream and Vanilla
Pour in the heavy cream (or milk), vanilla extract, and salt. Increase the speed to medium and beat for 3-4 minutes, until the frosting is light, fluffy, and smooth. If the frosting is too thick, add a tablespoon more of cream until it reaches your desired consistency.
Adjust Consistency
For a thicker frosting, add a little more powdered sugar. For a softer frosting, add a bit more cream or milk. The frosting should be smooth, fluffy, and spreadable.