I'm no stranger to cookie-themed ice cream; in the last year alone, I've tackled Oreo and Biscoff ice creams, both of which start with homemade cookies steeped straight into the base. Whether it's the jet-black punch of Dutch cocoa in the homemade Oreo cookies or the cinnamon and caramel intensity of made-from-scratch speculoos, those cookies are bold enough to be diluted in a dairy-rich ice cream base and still come through with big flavor.
But that approach won't cut it for the mellow profile of an oatmeal cookie, scented with the delicate aroma of baked oats and underscored by a hint of molasses, cinnamon, and vanilla. Drown a cookie like that in milk, and all its nuance will disappear. Oatmeal cookie ice cream requires a different strategy, one that infuses the custard with the flavor of toasted oats from the inside out, then bolsters it with a backbone of brown sugar and spice. And let's not forget all the chewy, crunchy textures essential to classic oatmeal cookies.
It's a tall order, but not a far-fetched one. And fortunately, I'd ironed out a blueprint with the toasted-rice-and-vanilla-bean ice cream from my cookbook. It starts with plain rice toasted in a skillet, a process that brings out all the rice's nuttiness while limiting the thickening power of its starch,* leaving just enough to keep the ice cream silky-smooth without edging into a sense of gumminess. It's not that starch is inherently bad for ice cream—I use a bit of cornstarch to keep my Meyer lemon ice cream super creamy—but when grain is the primary flavoring agent in an ice cream, the high proportion of starch can make for a weirdly chewy texture, and toasting helps tame that effect.
With all that in mind, this recipe does the same thing with old-fashioned rolled oats, which I toast in a saucier until pale gold and fragrant. From there, I add the dairy, along with a cinnamon stick and a split vanilla bean for that oatmeal cookie vibe. For this application, feel free to use a vanilla bean left over from another project if you happen to have one on hand, or grab a fresh one for the occasion. The vanilla intensity will vary, of course, but even a leftover vanilla pod still has lots of flavor left to give.
When the dairy is bubbling-hot, I shut off the heat, cover, and steep the mixture for about four hours. Sure, you can scrape by with less time, but it's a waste of whole spices to rush the process. A longer timeline helps pull out a deeper, more complex range of flavors and aromas than you can achieve with ground spices and vanilla extract alone—ingredients that will also be added later on. Generally speaking, using the same ingredient in different formats can help to broaden the spectrum of flavor in desserts. (I do the same with cocoa powder and dark chocolate in brownies, both fancy and plain; with fresh and freeze-dried fruit for strawberry layer cake; with wild and cultivated blueberries for pie; with coconut milk and coconut flour for layer cake; et cetera, et cetera.) Creating these layers of flavor is especially important in ice cream, where the cold serving temperature works to dull our sense of taste.
After steeping that first layer of flavors, I make the custard base by combining egg yolks and brown sugar with ground cinnamon and salt, then whisking in the infused oat milk (with the cinnamon stick and vanilla set aside—I'll deal with them again later).
Since the infused oat milk won't be hot after a few hours of steeping, this step isn't like traditional tempering at all; you can simply whisk in the liquid all at once to combine, since there's no risk of the egg scrambling.
Next, I return the base to the saucier and warm it over medium-low heat, stirring with a flexible spatula until the liquid is warm to the touch. Then I crank the heat up to medium and begin stirring with a little more care to prevent any curdling around the surface of the pan. It'll be done when the base is steaming-hot, around 155°F (68°C) or so. This figure is less about precision than about context; the base should be hot but nowhere near boiling. Spotting a few wisps of steam is a good enough indicator for me.
From there, I pour the hot custard through a nonreactive fine-mesh sieve, using my spatula to press the oats until they give up all that flavorful milk. Finally, I stir in a bit of vanilla extract and return the cinnamon stick and vanilla pod to the base. This allows them to continue infusing as the mixture cools, building in more flavor over time.
I often use an ice bath to speed the cooling process when making ice cream, but thanks to that secondary infusion, this recipe benefits from a slower pace. For that reason, I recommend cooling it overnight in the fridge, although it will technically be ready to churn as soon as it cools to 39°F (4°C). I swear, though, giving it the extra time is worth the wait.
The real act of patience, however, is to refrain from devouring the toasted oats, still warm from poaching in cinnamon- and vanilla-scented milk and lightly sweetened with a hint of brown sugar. Cross my heart, it's the most extraordinary bowl of oatmeal in the world, but it also has the potential to become the ice cream's key feature: baked oatmeal clusters.
As with my buttermilk granola, soaking old-fashioned rolled oats in dairy helps each flake swell in the oven, so it turns porous and crisp as steam escapes. Meanwhile, the added lactose and dairy fat soaked up from the ice cream base help the oats develop a rich and nutty flavor as they brown, lending a sense of butteriness to the cookie ice cream. Once frozen, the small flakes get a little crunchy, while the bigger pieces retain a hint of chewiness, creating the same range of textures found from edge to center in an oatmeal cookie.
Once the ice cream base is cold, it's time to remove the cinnamon stick and vanilla (scraping both clean) and start churning! My favorite small-batch machine is the Cuisinart Ice-21, a freestanding machine that's cheaper and more effective than any stand mixer attachment. Plus, when not in use for ice cream, it's the best ice bucket for rapidly chilling a bottle of wine.
Let the ice cream churn until it's fluffy and thick, a step that ensures it'll be light and easy to scoop even straight from the freezer (while under-aeration will make ice cream like this seem gooey and dense). Before taking it off the machine, add the prepared oatmeal clusters, along with toasted pecans and dried fruit to taste.
If you prefer smoother ice cream styles, you can reserve these mix-ins to use as a topping instead. But, for a true oatmeal cookie experience, I want those chewy, crunchy, nutty elements mixed into every bite.
Best of luck saving any for later, because when this is coming right out of the machine, the only real course of action is to grab a spoon. But if you do have the capacity for restraint, scrape the ice cream base into a chilled container, whether that's an empty yogurt tub, a specialized ice cream container, or simply a nonreactive loaf pan.
For a true ice cream parlor feel, sprinkle some more dried fruit, nuts, and oat clusters on top.
And don't be shy!
Now for one final act of patience—letting the ice cream ripen. Press a sheet of plastic wrap directly against the surface of the ice cream, then cover with a lid or a sheet of foil. The exact amount of time needed for the ice cream to freeze will depend on the depth and surface area of the container, but for picture-perfect scoops, overnight is best.
Between the toasted-oat infusion and the brown sugar ice cream base, along with dueling layers of cinnamon and vanilla (plus chewy-crunchy bites of oat clusters, dried fruit, and toasted pecans), the overall profile is 100% oatmeal cookie—even without any actual oatmeal cookies.
It's as sophisticated a scoop as you'll find in any shop, but all the more fun to dig into because it's homemade.