Add softened butter to a stand mixer fitted with a paddle attachment. Mix for about 2 minutes until the butter is lighter in color and fluffy in texture.
Add sifted powdered sugar, one cup at a time, mixing completely between additions. Always start the mixer slowly so the powder doesn't explode out the top. A tea towel over the mixer also helps keep the powder in the bowl.
Add salt, cream of coconut, vanilla bean powder, or the vanilla extract. Blend on low speed until combined.
Scrape down the side of the bowl, and then beat on high for 3-4 minutes until the buttercream is nice and fluffy. Adding air creates a light, fluffy texture that pipes beautifully.