Place the softened butter and cream cheese in a stand mixer fit with the whisk attachment. Beat the butter and cream cheese together until homogenous and fluffy, about 2 minutes.
Scrape down the bowl.
Add the vanilla extract, salt, and powdered sugar and whip to combine. After about a minute of mixing, use a rubber spatula to scrape down the bowl and beat for 2 more minutes until light and fluffy.
Use to frost your cakes as needed!
Notes
Make sure your butter and cream cheese are true room temperature to prevent and clumps or splitting!
The whisk attachment will help to get your frosting light and fluffy.