Exceptionally Smooth Homemade Ice Cream

I've always found that I appreciate a new dish much more when I know a little about its roots. But the first time I tried the ice cream called crema morisca in the square of the old walled city of Campeche in Mexico, I realized that this was a dessert that needed no help from history. Its subtle flavors drew me in—dried plums, vanilla, a hint of sweet sherry, and something richer than cream—but its exceptional texture was what won me over. It was soft, velvety, and perfectly smooth.

After sampling that ice cream and then finding a recipe for it in a regional cookbook, I began to pay more attention to Mexico’s other versions of the frozen treat that may be the world’s favorite indulgence. What I discovered was something that I should have known all along: that Mexican cooks have applied the same ingenuity to making ice cream that they have to every other aspect of their cuisine.

Evaporated milk for super-creamy texture

Historically, cooks in Mexico have had to overcome considerable challenges in the kitchen, including a shortage of refrigeration. As a result, evaporated milk is used in recipes where we would use fresh milk and cream. This substitution happens to work extremely well in ice cream. Evaporated milk has a high concentration of milk solids, and this gives a richness and smoothness to ice cream. Of course, these ice cream recipes do include some heavy cream and milk, too, but it’s the addition of evaporated milk that gives them such a creamy, custardy texture.

I don’t know how cornstarch found its way into Mexican ice cream, but its presence makes sense. Cornstarch lets the custard base thicken with fewer egg yolks (which means fewer calories and less saturated fat). It also helps protect against curdled eggs so the custard can be cooked over direct heat—rather than in a double boiler—without the usual worry that you’ll end up with scrambled eggs.

The chocolate ice cream calls for two unusual ingredients: Mexican chocolate and cajeta . Mexican chocolate is sweeter than most and flavored with cinnamon and often with ground almonds. Cajeta (pronounced kah-HAY-tah), sometimes called leche quemada (“burned milk”) or dolce de leche, is nothing more than milk (usually goat’s milk) simmered with sugar and perhaps vanilla, until it’s syrupy thick and golden brown. In Mexico, cajeta is used as a dessert topping, a crêpe filling, in candies, or anywhere else that a rich, creamy, sweet flavor with considerable depth is desired. Look for Mexican chocolate and cajeta in Mexican markets or order it by mail. The homemade version of dolce de leche that I suggest in the recipe is a fast and easy substitute.

A well-chilled custard base for a faster freeze

Other than the innovations mentioned above, these ice creams follow the same method as most others: make a custard base, cook it until it thickens, chill it, and spin it in an ice-cream machine until frozen.

Cooking the base does two things: it heats the milk (essential for a smooth texture), and it eradicates any concerns about salmonella in the eggs (the bacteria can’t survive above 160°F). To avoid overcooking the custard, take the following precautions:

• Add the milk to the egg yolks gradually. Adding eggs abruptly to a very hot mixture can cause them to curdle. To increase their temperature gradually, whisk a bit of the hot liquid into the yolks before mixing them into the rest of the hot mixture, a process called tempering.

• When the custard is ready, stop the cooking. As the custard nears 180°F, it begins to thicken very quickly. To halt the cooking, remove the pot from the heat and mix in the remaining ingredients, which should be chilled.

You could set up an ice bath to cool the custard  even faster, but it’s an extra step that’s easily omitted. Even if a few specks of cooked egg are in the custard, it isn’t the end of the world: you’ll be straining the mixture before chilling it.

I’ve had great results by refrigerating the custard base for as little as two hours or for as long as 24 hours before pouring it into an ice-cream machine. Just keep in mind that the colder the base is, the quicker and easier it will freeze.