Make sure the butter and cream cheese are at room temperature.
Add them both to your mixing bowl and beat until fully combined.
Slowly add the powdered sugar to the butter and cream cheese mixture until fully combined. Scraping down the sides as you go to make sure there are no lumps or dumps hiding anywhere.
Add the vanilla, and 1 tablespoon of the heavy cream. Whip until it starts to become light and fluffy.
If you need the 2nd Tablespoon of heavy cream to reach your desired consistency, add it now.