Beat the butter first. Add butter to a stand mixer with the whisk attachment, or use a hand mixer. Beat on medium speed for 2–3 minutes, until smooth, creamy, and slightly lighter in color. Scrape the bowl well.

Add the sugar gradually. Add the sifted powdered sugar 1 cup at a time, mixing on low after each addition. Scrape the bowl after the second addition.

Add salt, vanilla extract, vanilla bean paste, and 2 tablespoons of the cream. Beat on medium-low for 1 minute. Add the remaining tablespoon cream if needed.

Whip, rest, then smooth. Beat on medium speed for 1–2 minutes until fluffy and creamy. Let the frosting sit for 5 minutes, then beat on low for 1 minute. (The short rest helps the powdered sugar hydrate and softens its gritty taste).

Adjust the texture. For stiffer piping, beat in more powdered sugar 2 tablespoons at a time. For spreading on a sheet cake, beat in more cream 1 teaspoon at a time. Before using, stir vigorously by hand with a spatula for 1–2 minutes to remove any air bubbles.