Beat the butter until smooth in a large bowl or stand mixer. Add brown sugar and cream until fluffy, 2-3 minutes.
Add vanilla, heavy whipping cream and salt and mix until combined.
Reduce mixer to medium-low speed and while mixer is running, slowly add powdered sugar and mix until smooth, about 1-2 minutes. Then increase the mixer to medium-high and beat until fluffy and light, about 5 minutes.
Frost cupcakes as desired
