In the top of a double boiler, whisk together egg whites and sugar. Place over simmering water and cook, without stirring, until an instant-read thermometer registers 140°.
Immediately pour mixture into the bowl of a stand mixer fitted with the whisk attachment. Beat at high speed until fluffy, white, and glossy, about 10 minutes. Use immediately.
Recipe by Victoria at https://victoriamag.com/eggnog-pots-de-creme-toasted-meringue-recipe/