Place the butter in the bowl of a stand mixer set with the paddle attachment.
Beat to butter on medium speed for 3 to 5 minutes or until butter is light and creamy.
Turn the speed of your mixer down to the lowest number, then start adding the powder sugar little by little alternating with the heavy cream. Use a spatula to disperse the sugar. (prevents major clean ups)
Add the vanilla and the salt.
Once you have added all the ingredients and they have incorporated turn the speed of your mixer up to medium-high (speed 4) and let it cream for 2 to 4 minutes. If you wish to add color to your buttercream this is the time to do so.