Soften the butter: Let the butter sit at room temperature until it yields easily when pressed. This helps create a smooth, fluffy texture without lumps.

Cream butter and marshmallow: In a large mixing bowl, beat the softened butter on medium speed for 1–2 minutes until creamy. Add the marshmallow creme and beat another 1–2 minutes until fully combined and slightly airy.

Add vanilla and salt: Mix in the vanilla extract and a pinch of salt. The salt is important—it keeps the frosting from tasting flat or cloying.

Incorporate powdered sugar: Add the powdered sugar in 2–3 additions, mixing on low after each to prevent a sugar cloud. Once it’s mostly incorporated, increase to medium and beat until fluffy.

Adjust the texture: Add 1 tablespoon of cream or milk and beat for 30–60 seconds. If you want a softer, more spreadable frosting, add the second tablespoon. For piping, keep it slightly thicker.

Whip for lift: Beat on medium-high for 1 more minute to add volume. The frosting should look glossy, smooth, and hold soft peaks.

Frost or pipe: Use right away to frost cooled cakes or cupcakes. If piping, transfer to a piping bag with your favorite tip.