Swiss Buttercream is a little more time consuming to make than many of the other icings in this book because it requires a few more steps, but it is still quite simple. The slight sheen and smooth texture make it a beautiful icing to use for more formal cakes, and a bubbly, dry champagne pairs well with this icing, making it just the thing for celebratory occasions. While useful, a candy thermometer is not required. When you are heating the egg whites, just make sure that the sugar has dissolved entirely and the mixture feels hot to the touch before you whip the egg whites to a meringue. For best results in rebeating cold Swiss Buttercream, take about one-quarter of the icing and microwave it for 1 minute, until melted. Pour the melted icing over the cold icing, then beat it in a standing mixer fitted with a paddle attachment at high speed until it is smooth and fluffy, 3 to 5 minutes.
