In the top of a double boiler, whisk together egg whites and sugar. Cook, whisking constantly, over simmering water until a candy thermometer registers 140°. Remove from heat.
Pour mixture into the work bowl of a stand mixer fitted with the whisk attachment. Beat at high speed until thick, white, and fluffy, about 10 minutes. Use immediately.
Recipe by Victoria at https://victoriamag.com/bourbon-molasses-eggnog-with-torched-meringue-recipe/