Add the softened cream cheese and butter to a large mixing bowl.
With an electric mixer, beat the cream cheese and butter for 2-3 minutes, until smooth.
Add the vanilla extract and salt.
Mix until combined. Scrape down the sides of the bowl as needed.
Add the unsweetened cocoa powder and half of the powdered sugar to the bowl.
Mix on low until combined, and then increase the speed to high and beat for 1 minute.
Add the remaining powdered sugar and mix until combined.
Add the milk.
Mix on low for 1 minute until incorporated and then increase the speed and beat for 2 minutes, until smooth. Scrape down the sides of the bowl with a rubber spatula as necessary.
Frost your cake or cupcakes immediately or place in the refrigerator until ready to use.