Add butter and cream cheese into the mixer and cream until fluffy
Add powdered sugar, cocoa powder, vanilla, salt, and heavy cream, and mix throughtly (about 4-5 minutes) scrape down sides occasionally to make sure everything is incooperated evenly!
Notes
This frosting can be made up to 3 days in advance. After whipping, place frosting in an airtight container and seal. Refrigerate until ready to use, then bring to room temperature and mix well before frosting.