Of the three types of meringue, Swiss meringue is perhaps the easiest for the home cook to master. This recipe is by no means as simple as the Easy Chocolate Buttercream on page 432, but it is a good next step on the way to more involved icings such as Italian meringue. You begin by combining egg whites and sugar in a mixing bowl and then whisking them over a pan of simmering water. Because the heat is more gentle, you won’t have to use a candy thermometer. Once the sugar has melted, and the egg whites are warm, the bowl is transferred to an electric-mixer stand and the mixture whipped to stiff peaks. When the mixture is completely cool, softened butter is beaten in piece by piece, to create a silky smooth icing. It is ultrarich and delicious, and can be used on cakes that run the gamut from homespun to oh-so-fancy.

　　

Ingredients

makes about 6 cups

　　1 1/2 cups sugar

　　6 large egg whites

　　Pinch of salt

　　1/4 teaspoon cream of tartar

　　1 pound (4 sticks) unsalted butter, cut into tablespoons, room temperature

　　1 teaspoon pure vanilla extract

　　

Step 1

Heat sugar and eggs Bring a saucepan filled with about 2 inches of water to a simmer. Meanwhile, combine sugar, egg whites, and salt in a large heatproof mixing bowl. Set bowl over (not in) simmering water, and whisk until whites are warm to the touch and sugar is dissolved, 2 to 3 minutes. (Heating the eggs relaxes their proteins, enabling the eggs to whip up higher and more quickly; the sugar also melts, for a silky smooth consistency.) Test by rubbing between your fingers; the mixture should feel smooth.

　　

Step 2

Whip meringue Attach bowl to a standing electric mixer fitted with the whisk attachment, and beat on low speed until foamy. Add cream of tartar, and beat on medium-high speed until stiff, glossy peaks form and mixture is cooled completely, about 10 minutes.

　　

Step 3

Mix in butter Reduce speed to medium-low; add butter 2 tablespoons at a time, beating to incorporate fully after each addition. Don’t worry if the buttercream appears curdled at this point; it will become perfectly smooth again with continued beating. After all the butter has been incorporated, beat in vanilla.

　　

Step 4

Finish Switch to the paddle attachment. Beat on the lowest speed to reduce air bubbles, 3 to 5 minutes. Let stand, covered with plastic wrap, at room temperature. (If not using the same day, transfer to airtight containers and store in the refrigerator up to 3 days or the freezer up to 1 month. Before using, bring to room temperature; beat with the paddle attachment on the lowest speed until smooth and pliable, about 10 minutes.)

　　

Chocolate Swiss Meringue Buttercream

Step 5

Follow recipe above, adding 5 1/2 ounces melted and completely cooled semisweet chocolate along with the vanilla.

　　Reprinted with permission from Martha Stewart's Cooking School: Lessons and Recipes for the Home Cook by Martha Stewart. Copyright © 2008 by Martha Stewart. Published by Crown Publishing. All Rights Reserved.Martha Stewart is the author of dozens of bestselling books on cooking, entertaining, gardening, weddings, and decorating. She is the host of The Martha Stewart Show, the Emmy-winning, daily national syndicated program, and founder of Martha Stewart Living Omnimedia, which publishes several magazines, including Martha Stewart Living; produces Martha Stewart Living Radio, channel 112 on SIRIUS Satellite Radio; and provides a wealth of ideas and information on www.marthastewart.com.