In the bowl of a stand mixer fitted with the paddle attachment, mix together the sugar and butter. Mix on low speed until well blended and then increase the speed to medium and beat for another 3 minutes. Add the salt, vanilla, and cream. Beat on medium for 1 minute, adding more cream if needed.
Storage - Transfer to airtight container and store in fridge for up to a week or in the freezer for up to 3 months. When time to use, let come to room temperature and re-whip in the stand mixer until light and fluffy.