Everyone loves the idea of a secret ingredient, a pinch of a mysterious something that elevates a recipe. But, as with many types of sorcery, this power comes at a cost. So it goes with this outrageously purple ice cream, which trades the romance of fresh, seasonal fruit for the sheer power of its freeze-dried form.
If you're a regular here at Serious Eats, you probably know that I have an obsession with freeze-dried fruit—in thick and stable whipped cream, in a rainbow of no-bake cheesecakes, and in Technicolor strawberry buttercream.
For newcomers, I'll put it like this: Freeze-dried fruit is pure fruit, minus the water, with no added sugar. It's produced using a manufacturing process that avoids heat altogether, which keeps its flavor fresh and bright.
Unlike leathery dried fruit, freeze-dried can be ground into a fine, dry powder that dissolves readily in liquids, and because it contains no water or added sugar, it won't wreck a dessert's consistency or sweetness. That's an especially useful attribute in ice cream, as it can turn icy and bland when made with a straightforward fruit purée (which is, sadly, mostly water). Meanwhile, freeze-dried fruit will absorb moisture from the ice cream base, actually improving its stability and texture.
The downside is that we tend to be most drawn to ice cream in the summer, which is exactly when fresh fruit is at its most irresistible. Which isn't to say you can't grab that fruit to make a delicious topping, or us it for recipes designed to take that water content into account (like, say, roasted-cherry ice cream)—only that this particular recipe works best with freeze-dried fruit. Save the fresh stuff for toppings and pie!
While I'm using blueberry ice cream as an example, this recipe will totally work with any type of freeze-dried fruit, so use whatever you can find, or special-order whatever you like.
Brick-and-mortar supermarkets like Trader Joe's, Whole Foods, and even Kroger produce their own house brands, while many other groceries sell freeze-dried fruit from companies like Karen's Naturals and Natierra.
Or, you can shop online at Amazon, where you'll find freeze-dried versions of all the supermarket basics (berries, banana, apple, mango, tangerine, and cantaloupe), as well as specialty fruit flavors like dragon fruit, pomegranate, goji, black raspberry, and even durian.
Which is to say, choosing freeze-dried fruit over fresh isn't going to limit your options.
It's a simple mixture of sugar and egg whites, with a bit of acidity from lemon juice or cream of tartar to help balance the sweetness, that's whipped until glossy and thick. The meringue provides structure and aeration to the ice cream in lieu of churning, but beyond that, it also serves as a neutral canvas for the fruit flavor, with none of the competing notes of custard from the yolks in a traditional ice cream recipe.
Richness, flavor, and a secondary element of aeration all come via whipped cream, doctored with the ground-up freeze-dried fruit. Unlike in my recipe for fruity food processor whipped cream, the cream here needs to be properly whipped. While the food processor technique is handy, it produces a rather dense whipped cream that, in turn, makes the ice cream too dense.
But with a traditionally whipped cream, even one thickened with freeze-dried fruit, there will still be ample aeration to keep the ice cream creamy and light.
Here, I've flavored the whipped cream with a bit of coriander as well, which helps to coax out the best in blueberries, but it's an optional ingredient that can be omitted, or adapted to other fruits. For example, Chinese five-spice powder works brilliantly with strawberry, while cloves help play up the natural flavor of banana.
The prepared meringue is gently folded into the blueberry whipped cream, along with a small splash of booze. This can be something like limoncello to highlight the fruitiness of the blueberries, or you can opt for the more complex flavors from Smith & Cross Jamaica Rum (which has a curiously strong note of blueberry). Other fruit flavors call for other spirits: silver rum with banana, or framboise with raspberry.
When the two are well combined, transfer to a large, nonreactive container. I've lately been fond of using two-quart baking dishes, as they provide a great runway for scooping.
Cover with plastic wrap pressed directly against the surface of the ice cream, then cover again with a sheet of foil. Together, these layers will help minimize exposure to any funky freezer odors.
The ice cream's color (and flavor!) will deepen as the freeze-dried fruit powder hydrates over time, reaching its peak by the time the ice cream is fully frozen. How long that takes will depend entirely on your freezer settings and the size, shape, and material of the ice cream container, but expect to wait between six and eight hours.
The result will be a bright and flavorful ice cream that's creamy and easy to scoop, and utterly refreshing on a hot summer day.