(Adapted from the "Yuzu Ice Cream" recipe in Morimoto.)
"This ice cream is subtly flavored with yuzu, a citrus fruit favored by not only Japanese chefs, but by chefs everywhere who get to sample its inimitable taste. The juice can be had from the fresh fruit or is sold jarred or frozen in Asian specialty stores. When yuzu is not available, though, fresh lemon juice can be substituted."
2 large egg yolks
1/2 cup sugar
1 cup milk
1/2 cup heavy cream
1/4 cup yuzu juice (or fresh lemon juice)
In a heatproof medium bowl, beat the egg yolks lightly. Gradually whisk in the sugar and beat until the mixture is thick and pale, about 2 minutes.
In a small saucepan, heat the milk until bubbles appear around the rim of the pan. Gradually whisk about 1/3 cup of the hot milk into the yolks to warm them. Slowly whisk the yolks back into the remaining milk in the pan.
Reduce the heat to low and cook, stirring, until the custard is thick enough to coat the back of a spoon. Strain into a clean bowl, set over a larger bowl of ice and water and stir until cooled.
Whisk in the heavy cream
and yuzu (or lemon) juice.
Cover and refrigerate for 1 to 2 hours, until chilled.
Pour into the canister of an ice cream machine and process according to the manufacturer's instructions. Transfer to a covered container and freeze for at least 3 hours, or overnight, until firm enough to scoop.