I’d come to Trattoria Masuelli San Marco—an unpretentious father/son-operated eatery just outside Milan’s city center—to learn the region’s signature golden saffron risotto. It didn’t disappoint. But it was the risotto’s sweet counterpart—a bowl equal in its creamy-smooth richness—that was the surprise hit.

I mistook it for zabaglione, the classic Italian dessert of whipped egg yolks, sugar and sweet wine, often Marsala. One bite made clear this was no zabaglione. Delicious as that custard can be, it too often is heavy, overly sweet and boozy. This was airy and light, tasting of egg and vanilla, a dusting of cocoa powder adding complexity.

The father, Max Masuelli, explained. While zabaglione is made only from egg yolks—and is cooked over the gentle heat of a double boiler—this dish uses both the yolks and whites. And it is uncooked, bringing it closer to a French mousse.

The yolks are whisked into mascarpone, a soft, unsweetened Italian cream cheese. This gives the dessert—called crema al mascarpone—body without cloying sweetness. In fact, the whole recipe calls for just 3 tablespoons of sugar. The cheese mixture then is folded together with the egg whites, which are whipped until pillowy.

Adapting this recipe for Milk Street was easy. We varied from Masuelli’s method only once. All that talk about zabaglione made us miss the richness a little liquor can add. Just a splash of dark rum got us the flavor we wanted. The result was a quick, simple dessert that is satisfyingly sweet without overwhelming.