You're not thinking about ice cream at all; you're thinking about a frozen soufflé.
Now you're never going to catch me saying anything bad about ice cream, particularly the homemade kind. But ice cream has a certain aesthetic. It's homespun, like summer evenings on the porch with an old-fashioned wood-slatted churn and a box of rock salt.
A frozen soufflé offers a decidedly different approach, sheer as chiffon and drop-dead elegant.
There are really two slightly different styles of frozen soufflé; which you choose will depend on what kind of dessert you're looking for. Both are relatively easy to make -- only a little more complicated than homemade ice cream -- though they both require a bit of attention to process.
One frozen soufflé is light and airy and offers direct, clean flavors. It's based on what's called an Italian meringue, essentially beaten egg whites that have been cooked by slowly pouring in a very hot sugar syrup while the mixer is still running.
The other is creamier, with a rich eggy flavor underpinning whatever else you decide to add. You base this one (technically a Bavarian cream) on a kind of custard -- egg yolks cooked gently with sugar until they're thick.
Neither of these processes is for the kitchen newbie. Eggs are notoriously temperamental, and if you're not comfortable beating egg whites to a stiff peak, you're probably not quite ready to whisk in a softball sugar syrup to finish the meringue, either.
But if neither of those tasks scares you, you'll find that these recipes come together easily and the results certainly outweigh the slightly higher degree of difficulty. The key is organization -- and having a good supply of mixing bowls at hand.
Before you begin, have the fruit cooked, strained and cooled (a food mill will purée and strain the seeds and peels at the same time). Have the egg whites at room temperature and the whipping cream chilled to ensure you get the most volume out of each. Have the collar attached to the soufflé dish. Now you're ready to go.
Cooking the custard
To make the custard base, whisk egg yolks and sugar in a mixing bowl you've propped over a bowl of simmering water. You want to cook them over gentle heat, so don't let the water boil and don't let the the bowl touch the water. Also, lift the edge of the bowl from time to time to let some steam escape. (Careful, it's hot! Use a dish towel or oven mitt.)
The egg yolks will turn pale gold and then swell and thicken. You'll know the mixture is ready when it is thick enough to coat the back of a spoon and when you don't feel any raw sugar when you rub a bit of the custard between your fingers.
Don't look now, but you've just made zabaglione (if you whisk in some Marsala or another flavoring) and you're well on your way to crème anglaise (if you stir in scalded milk and cook until that thickens).
Now fold the puréed fruit into the custard, fold the custard into the egg whites and fold the egg whites into the whipped cream. In the case of the egg whites and whipped cream, you'll get better results if you lighten the base with a bit of each before adding the rest.
Fold gently, but mix thoroughly. Remember that egg whites and whipped cream are mainly masses of air bubbles that will make the soufflé light and delicate if you keep them intact, or heavy and dense if you don't.
Use a spatula to cut straight down into the center of the mixture and then gently scoop and fold over top. Turn the bowl as you're working. It'll probably take a dozen folds to get a homogenous mix.
Gently pour the mixture into the prepared soufflé dish and freeze. It'll take at least four hours to get solid, and after that it'll last for a day or two without any ill effects. Bring it out to warm slightly before serving. The texture should be creamy, not icy.
Eye on the meringue
The Italian meringue soufflé takes fewer steps, but it does require a little more attention to temperature.
Start by bringing sugar, water and a little corn syrup to a boil in a small saucepan. Cook it until the temperature reaches 235 to 240 degrees on a candy thermometer. This is called the "soft-ball" stage because if you drop a little of the syrup into a glass of water, it will form a soft, pliable ball (I've seen Jacques Pépin test this with his bare fingers; for the rest of us mortals, a candy thermometer is definitely preferred).
It'll take 10 to 15 minutes to cook the sugar down. Once the mixture becomes clear -- there is no sugar visible in the water -- stop stirring. Sugar cooked to these concentrations is prone to crystallize, and once this starts, things go bad really quickly, like the Ice-9 in Kurt Vonnegut's "Cat's Cradle." Adding a little corn syrup will reduce the chances of this, but it can still happen if you're sloppy. Brush the sides of the pan down with a little water if you see crystals forming there.
The good news is that the syrup cooks by itself without much checking from you. So while it is boiling, beat the egg whites to stiff peaks. Remember, you want to whip them long enough that when you lift the beater, you get a sharp point that doesn't fall over. Don't over-beat, though, or the egg whites will turn grainy.
When the egg whites are stiff and the syrup is done, leave the mixer running and slowly pour the syrup down the side of the mixing bowl (if it hits the beater, you'll get gummy sugar strings).
This is one of the coolest things in cooking: The egg whites, which look airy and delicate at first, will billow and swell enormously and turn snowy white with a texture like the inside of a s'more.
Keep beating until the outside of the mixing bowl is cool to the touch, another three to five minutes. Then fold in the fruit base and the whipped cream. Freeze and that's it.
Each of these techniques has its own qualities and there is no right or wrong answer when it comes to which you choose.
In developing these recipes, I chose blackberries for the Italian meringue soufflé, focusing on the sharp, bright side of their flavor. But you could just as easily pair them with the custard soufflé, and the result would be more about contrasting that flavor with the richness of the egg yolks.
The same is true of the peach soufflé. I chose the custard base for this and the result is subtle, a delicate peaches-and-cream start followed by a haunting aroma of fruit that lingers. Made with the Italian meringue base, the flavor would have been much simpler and pure "peachier."
Of course, you can also substitute whichever ripe seasonal fruit you prefer in either soufflé. Just remember that you'll need about 2 cups of it after cooking and straining. Whoever heard of something so elegant being so accommodating?