Depending on what recipes we're testing in a given week, the refrigerator in the SAVEUR test kitchen is frequently stocked with quart containers filled to the brim with egg whites. Though perfectly suitable for any number of uses, the whites sometimes wind up in the trash before I've settled on a good use for them, because I try to think beyond such standards as angel food cake and meringue. While testing several recipes for an upcoming issue that rely heavily on egg yolk-thickened bechamel sauces, we again had a glut of extra egg whites. Normally, I'd contemplate for days or even weeks what to make with them, and they might go bad before I'd made up my indecisive mind. But with the surge of warm weather we had over a recent weekend in New York City, I actually felt like eating angel food cake. I knew the exact recipe I wanted to use, too.