As a Kentuckian born and raised, buttermilk* is an ingredient I can count on having in my fridge just as surely as eggs and cream. I use it in everything from the buttermilk biscuits in my cookbook to giant pans of Texas sheet cake (not to mention crispy homemade granola, fluffy gingerbread, blackberry cobblercheddar drop biscuits, and the fastest, easiest waffles in the world).
*Please, don't get me started on the folly of buttermilk substitutes.
All that is to say, buttermilk is one of my top five must-have ingredients—not just for baked goods, but for custards and ice cream, too.
Buttermilk gives ice cream a fresh, tangy flavor not unlike frozen yogurt, but leaner and therefore even more refreshing (historically, buttermilk was lowfat by nature, a byproduct of churning butter; modern manufacturing methods may not be the same, but lowfat buttermilk has a flavor more consistent with the original).
Having experimented with a few different approaches to buttermilk ice cream (including attempts with both fior di latte and ice milk as a base, as well as traditional vanilla ice cream formulas), I was consistently dismayed. In these recipes, the texture proved either chalky or icy, or else its flavor failed to shine through, buried in the richness of yolks or cream.
These recipes use a combination of cornstarch and whole eggs to create a stable, light-bodied custard with fruit juice—a formula that proved ideal for working with an acidic, high-moisture ingredient like buttermilk.
By using it as a 1:1 swap for the fruit in these recipes, I made an intensely buttermilk-flavored ice cream that churned up as smooth as silk. Happily, this style of ice cream is also ridiculously easy to make, since it doesn't involve tempering.
Instead, the sugar (in this case lightly toasted sugar) and cornstarch are whisked together upfront, along with the whole eggs and buttermilk.
The custard is then cooked over medium-low heat until warmed through, then cooked over medium heat until bubbling hot. It's held at a boil for a minute, which eliminates any hint of chalkiness from the cornstarch, while also neutralizing a starch-dissolving protein found in egg yolks.
Once cooked, the custard is strained and whisked with cream. This helps cool the base a little faster, while also keeping the cream's flavor light and fresh.
Finally, the base is doctored with a spoonful of applejack and orange flower water.
Both of these ingredients infuse the ice cream with a light, fruity quality that highlights the tang of lactic acid in the buttermilk. If you don't have applejack on hand (alas, no spiked cider for you in the fall!), most any type of brandy will do, or else aromatic liqueurs on the floral-to-fruity end of the spectrum (like St. Germain, chrysanthemum honey liquor, or curaçao). The booze is an added bonus to the ice cream's flavor and texture, not a requirement, so don't stress it if dietary considerations (or an empty liquor cabinet) rule that out.
If you're in a hurry, the base can be cooled in an ice bath; otherwise, four to six hours in the fridge should do it. Either way, the goal is to bring it down to about 40°F before churning. As my friend Max Falkowitz has explained before, ice cream doesn't need to be chilled overnight.
If you use a machine like the one we recommend, be sure the freezer is set to 0°F (-18°C), or else the ice cream canister won't be cold enough to churn properly. Of course, that isn't a concern for machines with a built-in compressor, but it will affect the consistency of the ice cream during storage, so it's worth investigating none the less.
Whatever style of machine you have, be sure to churn the ice cream until it's light and thick enough to gather in the dasher.
If you stop when the ice cream has a runny, milkshake-like consistency, the ice cream may be dense, hard, and icy, as it hasn't been processed long enough to minimize fat and ice crystal size.
I love eating this buttermilk ice cream straight out of the machine, when it has a texture like soft-serve. That texture, combined with the bright tang of buttermilk, is reminiscent of the best frozen yogurt.
Otherwise, transfer the buttermilk ice cream to a chilled container and freeze until firm enough to scoop. Or, if you're feeling experimental, pair it with a fresh fruit swirl; it's particularly excellent with a blueberry ribbon.
Otherwise, the tanginess of buttermilk ice cream is perfect for serving peach galette or blueberry pie à la mode, where it's lightness helps keep the fruit flavor center stage. Or serve a warm slice of buttermilk gingerbread cake with a scoop of buttermilk ice cream instead of cream cheese frosting.
Which isn't to say you can't just enjoy this ice cream all on its own. With only two eggs, this ice cream doesn't have a strong custard flavor at all, only a gentle richness to tame the buttermilk's acidity into something mellow and smooth.