Airy yet satisfying, light yet rich, a chilled mousse sounds like a complete contradiction, doesn’t it? But this cool, luscious summer dessert is all that—and, as a result, it’s a true marvel. I love making a chilled mousse for summer dinner parties: It doesn’t heat up my kitchen, it must be made ahead, and it lends itself to being presented with a bit of panache. And best of all, from the very first spoonful, your guests will wonder how something so ethereal can have so much flavor.
A mousse is a base of flavored purée bound with egg yolks and sometimes a touch of gelatin and lightened with whipped egg whites and whipped cream. It can be made with many different flavors, but one of my summer favorites is this raspberry-blackberry version.
An intensely flavored base is key. Using the ripest berries will give the purée the bright flavor it needs so that the fruit shines through the eggs whites and cream.
For the airiest mousse with the best volume, follow a few tips. It’s easiest to separate eggs when they’re cold because the yolks are firmer. But do this before starting the recipe to let the whites warm up a bit: Egg whites at room temperature whip up to their most billowy and voluminous. Be sure that the bowl and beaters are completely dry and free of grease, as water or grease will keep the whites from attaining their fullest volume. Follow the cues in the recipe to know when you’ve beaten in enough air.
When whipping cream, be sure it’s well chilled. Cold cream whips up more easily into soft peaks. (A soft peak should fall back on itself when you lift the beater, and the cream will slide slowly when the bowl is tipped.)
Finally, folding in the whipped egg whites and cream is the most important step. Do this gently but firmly, so you maintain as much airy volume as possible but still have a well-blended mixture with no traces of white.