In the bowl of a stand mixer -- or in a large bowl and using a hand mixer -- beat the butter until light and fluffy, about 3 minutes. Scrape down the sides as necessary.
Beat in the powdered sugar until incorporated.
Then add the heavy cream, vanilla, and pinch of salt.
If the frosting is too thin, add a little more powdered sugar, a couple of tablespoons at a time. If the frosting is too thick, add a little more heavy cream, one teaspoon at a time.
Transfer the frosting to a piping bag fitted with a large piping tip to frost your dessert.
Notes
Servings: Makes enough frosting to frost a standard 8-inch round 2-layer cake, or 16-24 cupcakes, depending on how much frosting you use per cupcake.Substitutions: You can substitute regular milk or nondairy milk for heavy cream. Make vegan vanilla frosting: substitute your favorite vegan butter for the unsalted butter, and nondairy cream or milk for the heavy cream.Storage: Store frosting in an airtight container in the refrigerator for up to 3 days. When you're ready to use it, set it out and allow it to soften at room temperature before frosting.