Whisk the egg whites and sugar together in the bowl of a stand mixer. Place the bowl of the stand mixer over a double boiler and cook, stirring occasionally, until the egg whites are very warm to the touch and the sugar has dissolved.
Whip the egg whites on medium-high until stiff peaks form. Add in the salt and vanilla extract and whip to combine well. Cool slightly before using.
Yossy Arefi is a photographer and stylist with a passion for food. During her stint working in restaurant kitchens, Yossy started the blog Apt. 2B Baking Co. where, with her trusty Pentax film camera, she photographs and writes about seasonal desserts and preserves. She currently lives in Brooklyn but will always love her native city of Seattle. Follow her work at apt2bbakingco.blogspot.com & yossyarefi.com.