Add 1 pound room temperature unsalted butter to a large bowl and beat on high speed with a hand mixer or stand mixer fitted with the paddle attachment. Scrape down the sides and bottom of the bowl and beat again for 2-3 minutes, until the butter is smooth and pale in color.
Add half of the 8 cups powdered sugar to the bowl and mix on low until completely moistened, then increase the speed to high until fully incorporated. Add the remaining half of the powdered sugar and repeat, mixing on low until combined then slowly increasing to high and beating for 3-4 minutes until smooth and creamy.
Scrape down the sides and bottom of the bowl, then add 1 tablespoon vanilla extract, 1 pinch salt, and 3 tablespoons heavy whipping cream. Beat on high speed for 1-2 minutes, until fully combined and smooth.
Add more cream or a few tablespoons of powdered sugar to thin or thicken the frosting, and tint with food coloring as desired before using to frost your desserts.
Refrigerator: Store for up to 2 weeks. Bring to room temperature and rewhip before using. Add a splash of cream or powdered sugar to adjust the consistency if needed.
Freezer: Freeze for up to 3 months in an airtight container. Thaw overnight in the fridge, then rewhip and adjust the texture as needed.