Double-Boiler Marshmallow Frosting
Fresh egg whites make this frosting the real deal (versus using pasteurized meringue powder).
Double-Boiler Marshmallow Coffee Frosting:
In the top of a 2-quart double boiler combine 3/4 cup sugar, 2 tablespoons plus 2 teaspoons cold water (8 teaspoons), 1 egg white, and 1/8 teaspoon cream of tartar. Beat with an electric mixer on low speed for 30 seconds. Place over boiling water (upper pan should not touch water). Cook, beating constantly with the mixer on high speed, about 10 minutes or until frosting forms stiff peaks (tips stand straight) and an instant-read thermometer inserted in the mixture* registers 145°F for 3 minutes or 160°F for 15 seconds. Scrape pan occasionally. Remove pan from heat. Add 1 1/2 teaspoons coffee liqueur or strong brewed coffee and 1/2 teaspoon vanilla. Beat about 1 minute more or until frosting is fluffy and holds soft peaks (tips curl). Makes xx cups.