I’m a powdered sugar hater. It’s just sugar and cornstarch and in my opinion there’s really no need for cornstarch in frosting because the butter and chocolate make it thick enough.
Mix together everything but the melted chocolate in a stand mixer on high for 3 minutes, scraping down the sides so everything is incorporated. Add your melted chocolate slowly, scraping down the sides until it’s fully combined. Whip for about 5 minutes total; it should get lighter in color and fluffy. If you refrigerate it, just remix it for a minute before frosting.
