Meringue looks lovely and tastes delicious, and Italian meringue's unwavering stability allows the resulting desserts to be finished in the oven, frozen, or torched to dramatic effect.
Bring granulated sugar and 2/3 cup water to a boil in a small saucepan. Swirl pan to dissolve sugar. Wash down sides of pan with a wet pastry brush to prevent crystals from forming. Boil until syrup registers 238 degrees on a candy thermometer.
Meanwhile, put egg whites in the bowl of an electric mixer fitted with the whisk attachment, and beat on low speed until foamy. Raise speed to medium-high. Add cream of tartar; mix until stiff but not dry.
With mixer running, slowly pour in hot sugar syrup, and mix on high speed until mixture has partially cooled, 5 to 7 minutes. Reduce speed to medium, and slowly add confectioners' sugar. Raise speed to medium-high, and mix until mixture has cooled completely, 7 to 10 minutes more. Use immediately.