Foolproof Swiss Meringue

1 . Stage

Bring 2 cups of water to a simmer in a medium pot.

2 . Stage

Combine sugar, egg whites, salt, and cream of tartar in the bowl of a stand mixer.

3 . Stage

Reduce the heat under the simmering water and place the stand mixer bowl over the steam. Whisk egg whites lightly until a digital or candy thermometer inserted into the mixture reads 160 degrees F (71 degrees C), 6 to 10 minutes. Remove from the heat immediately.

4 . Stage

Place the bowl onto the stand mixer and attach the whisk attachment. Whisk on high speed until egg whites are cool and stiff peaks form, about 3 minutes; the mixture should hold peaks effortlessly and start balling up around the whisk attachment while appearing silky, shiny, and pure white.

5 . Stage

Use meringue immediately.