Salted Peanut and Caramel Tart

The peanut butter and marshmallow sandwich—the Fluffernutter—is inarguably all-American. Le Petit Grain, a Parisian boulangerie headed by Edward Delling-Williams, created a tartlet riff on that childhood favorite. A cookie-like pastry is filled with peanut butter meringue that is topped with caramel-coated roasted peanuts. For ease, we make a single 9-inch tart instead of individual tartlets. When making the meringue filling, pay attention to the timing in the recipe, which can be tricky. The whipped egg whites and sugar syrup need to be ready at the same time. If your egg whites reach soft peaks before the syrup is ready, reduce the mixer speed to low while you wait for the syrup to finish; this prevents the whites from turning dry and stiff. You’ll need a candy or instant thermometer for gauging the doneness of the sugar syrup. The finished tart will keep at room temperature for up to 12 hours. If you’re storing it longer than an hour or so, wait to add the flaky salt garnish until just before serving and cover the tart with plastic wrap or foil.