Beat butter in bowl of stand mixer for 3 minutes.
Beat in powdered sugar and salt until combined.
Add heavy cream and vanilla to the butter and powdered sugar. Whisk on high for 4 minutes until frosting is light and fluffy.
If the frosting is too thick, add more cream, 1/2 teaspoon at a time, until needed consistency is reached. Ensure the buttercream is slightly stiff.