To beat egg whites

In the bowl of a stand mixer fitted with the whisk beater, add the cream of tartar to the egg whites. Beat on medium-low speed until foamy. Gradually raise the speed to medium-high and beat until soft peaks form when the beater is raised. Gradually beat in the sugar and continue beating until stiff peaks form when the beater is raised slowly. For some recipes, such as The Renée Fleming Golden Chiffon, continue beating until very stiff clumps form when the beater is raised, about 2 minutes more.