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Growing up in Kentucky, I didn't have any opportunities to sample homemade semifreddo, and by the time I went to culinary school it seemed to have fallen out of fashion—or at least it was absent from the menus at the sort of restaurants I could afford to visit.
This gave it a somewhat legendary status in my mind, a mysterious dessert that I had never seen or tasted in the wild, something I avoided making at all cost for fear of doing it wrong. But at my second-ever job as a pastry chef, I was without an ice cream machine and miserable at the idea of a summer without a menu of frozen treats. So I conquered my fear of the unknown, read my way through a thousand cookbooks, and learned to make semifreddo.
It was glorious; like a cross between ice cream and mousse. The first bite was airy and soft, then creamy and rich as it melted, bringing out its full flavor. The first one I ever made, and the one I kept on my menu for a summer, was sweetened with locust honey (exceedingly common in Kentucky), and it's been my favorite semifreddo ever since. (I am, predictably, a sucker for nostalgia.)
What is Semifreddo?
Semifreddo means "half-cold," or "half-frozen," in Italian, a reference to the velvety softness that makes it seem like so much more than a frozen block of mousse. That texture has less to do with its literal temperature than its composition: a rich foam of eggs and cream with enough sugar to banish any trace of iciness, but not so much that it requires an ice cream machine to churn.
As with ice cream, which can be made with egg yolks, whole eggs, or no eggs at all, semifreddo can take many forms. Many recipes are based on meringue (whipped egg whites) or pâte à bombe (foamed egg yolks), and some use both. Historically, that's because whole eggs are difficult if not impossible to foam by hand; splitting up the yolks and whites makes each element easier to whip to its maximum potential.
Making the Case for Whole Eggs
Maximum aeration may be crucial for some applications, but that lightness isn't necessarily ideal for semifreddo. Sure, it needs some sense of airy loft, but one that's balanced by creaminess, too, and that's a feature more closely associated with density. The best semifreddos find a sweet spot between the two: light but creamy.
Knowing that the yolks and whites didn't need to be whipped to the utmost degree for my semifreddo, I had the freedom to streamline that multi-bowl process by whipping whole eggs instead. And, as I learned with homemade ladyfingers, foaming whole eggs is a cinch with a stand mixer.
Even so, whole eggs straight from the fridge can resist aeration even on the most powerful stand mixer, so the trick is to warm them to about 165°F over a water bath with a bit of sugar (or, in this case, honey) for insulation. Not only will this temperature cook the egg through, making it safe to eat, but partial coagulation allows whole eggs to whip with ease.
Setting up the Water Bath
I like to set up my water bath with the bowl of a Kitchen Aid Pro in a large pot or Dutch oven filled with an inch or two of water, plus a ring of tinfoil to act as a booster seat to keep the stand mixer bowl from making direct contact with the cooking vessel the water inside it (with stand mixer bowls that have a foot, it may be necessary to use a separate bowl for the water bath, as the foot can complicate conduction and, later, cooling).
This setup prevents the bowl from overheating by keeping it off the bottom of the pan or the water itself. Using a relatively large pot also prevents the bowl from acting as a lid, which would allow for a buildup of steam that could quickly scramble the eggs. But with a nice gap between the bowl and pan, that steam can freely flow, warming the eggs safely and efficiently. Plus, it's easy to see whether or not the water is simmering, or getting low, so that adjustments can be made accordingly.
Stovetop cooking also allows for a bit of evaporation, driving off some of the natural water from the eggs, further stabilizing the foam and ensuring a creamy semifreddo (sorry, sous vide enthusiasts). Once the egg and honey mixture reaches 165°F, I transfer the bowl to a stand mixer and whip to a thick, pale foam. This is the most important stage, so don't rush the process. Instead, rely on visual cues; the exact timing will vary depending on the power of a given mixer.
On a Kitchen Aid Pro, this takes about 8 minutes; while some variation is normal, the process can be delayed (or even prevented) if the stand mixer's bowl-to-beater clearance needs adjustment.
By the time the mixture is properly whipped, it will be cool enough to fold in a bit of stiffly whipped cream. To complement the honey used in the eggs, I like to flavor the whipped cream with a few drops of rose water and vanilla, but any sort of essential oil or extract can be whipped in, as well.
Bringing it All Together
Here, the purpose of using whipped cream isn't to add aeration per se, but to offset the deflating effects of pouring in liquid cream. For that reason, it's okay to minimize dirty dishes by whipping the cream in advance and storing it in the fridge until needed (because it's stiffly whipped, it will sit happily on a small plate). With a quick rinse, the bowl will be ready to re-use for the eggs. But it's okay to whip the cream to-order as well; the foamed eggs are stable enough to wait for the cream to whip.
I like to work in stages, folding in half the whipped cream at a time, to ensure each addition can be well incorporated without deflating the foam. Still, I'm not too fussy about it. An occasional fleck of cream won't hurt the semifreddo, but over-mixing (deflation) can make it seem hard and dense. So work gently, with an eye to creating an even mix, but don't pursue total homogenization at the cost of the semifreddo's airy structure.
Once mixed, scrape the base into a 9- by 5-inch loaf pan lined with plastic wrap, or a few criss-crossed sheets of parchment, to assist with unmoldding the semifreddo later on. Plastic wrap offers a more complete liner, but will wrinkle the surface of the semifreddo; parchment can be trickier and less complete for lining a loaf pan, but it will keep the exterior smooth.
In either case, wrap the loaf up tight and freeze until the semifreddo hits an internal temperature of about 0°F. Contrary to its name, the semifreddo is, in fact, fully frozen; it's just that the air and sugar in the mixture keep it soft and smooth, giving it a consistency that feels as creamy as if it were half melted.
Freezing may only take six to eight hours in a metal loaf pan, but for planning purposes the most practical option is to freeze it overnight—or longer. To me, it's far better to embrace the semifreddo's potential as a make-ahead dessert than desperately rush to make and serve it all in one day. Just make sure you pop a serving plate in the freezer, too; getting it nice and cold will maximize the semifreddo's life at room temperature.
To unmold, simply uncover the semifreddo, invert onto the chilled platter, and tug on the plastic or parchment to pull it free. Then, leaving the parchment or paper in place to protect the semifreddo, pop it back into the freezer until it's time for dessert.
How to Serve a Semifreddo
Ultimately, a semifreddo is like a giant sundae in loaf form, which is to say: pile it high with whatever toppings strike your fancy. Using toppings, rather than mix-ins, makes the semifreddo easy to slice; it may look beautiful studded with walnuts in that glossy food mag, but you'd need their stylist on hand to cut it for you. Toppings ensure clean slices, and the dreamy presentation is its own reward.
Because I didn't want to distract from the honey's floral aroma, I kept the toppings for this semifreddo rather simple: fresh cherries macerated with just enough sugar to draw out some saucey juice, and a scattering of Marcona almonds for crunch.
It would be just as lovely with a drizzle of dark chocolate and a handful of candied pistachios, but the combination of almonds and stone fruit is one of my favorites with honey. (Another favorite is rooibos caramel, but that's a recipe for another day.)
Semifreddo is a great party dessert, because it benefits from standing at room temperature for a minute or two before slicing, which means you're not in a mad rush and your guests have plenty of time to oooh and ahhh over the beautiful platter. Straight from the freezer, semifreddo can be slightly brittle, causing the slices to crumble or break. But when allowed to stand a moment or two at room temperature, it will slice like a dream.
Of course, semifreddo can be scooped like ice cream, but when you've got a half dozen friends around the table, slicing is infinitely faster than scooping, so you can get back to the party.