Before you begin, make sure the butter is at room temperature.
In a stand mixer with a paddle attachment, whip the room temperature butter on medium-high speed for five minutes. You will see a dramatic change-it will go from yellow to bright white and fluffy.
Sift the powdered sugar and add half to the mixer. Slowly increase the speed back up to medium-high and mix for five minutes. Scrape down the sides of the bowl and add the remaining powdered sugar. Slowly increase the speed again and mix for another five minutes.
Add the vanilla bean paste, 2 tablespoons of cream and mix to combine. At this point, check the consistency of the frosting. If you prefer to use a spatula to decorate the cake, you may want to add an additional 2 tablespoons of cream for a looser, more spreadable consistency.
Transfer the frosting to piping bags or decorate right from the bowl with a spatula. For best results, use immediately.