Italian meringue's unwavering stability allows the resulting desserts to be finished in the oven, frozen, or torched to dramatic effect. Use this to make our Lemon Meringue Semifreddi and Neapolitan Baked Alaskas.
Bring sugar, water, and corn syrup to a boil in a small saucepan, stirring until sugar dissolves. Cook, undisturbed, until syrup registers 248 degrees on a candy thermometer.
Meanwhile, whisk whites with a mixer on low speed until foamy. Add salt and cream of tartar. Increase speed to medium, and whisk until soft peaks form, about 8 minutes.
Reduce speed to low, and pour hot syrup down side of bowl in a slow, steady stream. Increase speed to high, and beat until mixture stops steaming, about 3 minutes. Use immediately.