This Swiss Meringue Buttercream frosting pairs beautifully with our Buttermilk-Chocolate Cake, but it would be delicious with almost any layer cake—it’s incredibly light and fluffy and doesn’t weigh down delicate cake layers. When making the frosting, add the butter slowly and don’t rush this step. It takes about 15 minutes to incorporate all of it. As you add the butter, the frosting may appear broken at some point, but it will come back together. Best of all, you can make it in advance; it’s surprisingly stable and will hold in the refrigerator for several days.
How to Make It
Step 1
Pour water to a depth of 1 1/2 inches in a large saucepan; bring water to a boil over high. Reduce heat to low, maintaining a gentle simmer. Whisk together egg whites, sugar, and salt in bowl of a heavy-duty stand mixer. Crumple a large piece of aluminum foil; shape into a ring about 2 inches high. Place in simmering water in saucepan. (The foil ring will prevent the mixer bowl from touching the water.) Place mixer bowl on foil ring.
Step 2
Cook egg white mixture, whisking constantly, until mixture registers 160°F on an instant-read thermometer, 10 to 12 minutes. Transfer bowl to heavy-duty stand mixer fitted with whisk attachment. Beat mixture on low speed for 1 minute; gradually increase speed to medium-high, beating until mixture is fluffy, glossy, and completely cool, 8 to 10 minutes total.
Step 3
Reduce speed to medium-low, and add softened butter a few pieces at a time, beating well after each addition. Beat in vanilla and almond extracts. Remove whisk attachment; attach paddle attachment. Scrape down sides of bowl with a rubber spatula. Beat frosting on low until very smooth, 1 to 2 minutes. Use immediately, chill in an airtight container up to 3 days, or freeze up to 1 month. (Before using, let chilled or frozen buttercream come to room temperature and beat on low speed.)
