In the bowl of a stand mixer with the paddle attachment, cream together the butter and cream on medium speed until light and fluffy.
Reduce mixer to low, and slowly add in powdered sugar, to prevent spilling. After powdered sugar has been added, return speed to medium to whip, about 2 minutes
While mixer is still going, add in vanilla extract, heavy cream, lemon juice (if using) and salt. Whip the frosting for another 2-3 minutes.
Frosting is now ready to use on your favorite baked items.
Notes: To store for future use in a covered container under refrigeration. Can be held for up to 7 days. Allow to sit at room temperature for at least 1 hour before frosting