This sherbet in waffle cups is the creation of Jorge Rocha Carmona and his wife, Claudia Mendez, owners of Rome Pastelera, Billy Cross's favorite pastry shop in Oaxaca.
Ingredients
2 teaspoons cornstarch
1 1/4 cups sugar
1 1/2 cups whole milk
1 large egg yolk
1/2 teaspoon finely grated fresh lime zest
1/2 cup fresh lime juice
2 cups plain whole-milk yogurt
Waffle Cups for serving, optional
Special equipment: an ice-cream maker
Directions
Whisk together cornstarch and 1 cup sugar in a 1 1/2- to 2-quart heavy saucepan, then slowly whisk in milk. Bring to a boil over moderate heat, whisking, then simmer, whisking occasionally, 2 minutes.
Whisk together yolk and remaining 1/4 cup sugar in a bowl and add hot milk in a slow stream, whisking constantly. Transfer to saucepan and cook over moderate heat, stirring constantly with a wooden spoon, until slightly thicker and a thermometer registers 170°F. (Do not let boil.) Pour custard into a clean bowl. Whisk in zest, juice, and yogurt. Chill until cold.
Freeze custard in ice-cream maker. Transfer to an airtight container and put in freezer to harden.
