In a small bowl melt the white chocolate in the microwave in 30-second intervals. Allow the fully melted chocolate to cool down for at least 10 minutes until it is room temperature, not warm to the touch.
In a large bowl add the softened butter and beat for 2-3 minutes until smooth and light. Reduce the mixer speed to low and slowly add in the cooled white chocolate until fully combined and smooth.
Add in the powdered sugar, vanilla, and salt and mix on low until nearly completely absorbed before increasing the speed to high. Whip for 2-3 minutes until smooth and fluffy. If the texture of the frosting is too thick, add 1 tablespoon of heavy cream and mix on medium-low to combine.