- 1 (14-ounces) package frozen naranjilla (also called lulo) purée, thawed (2 3/4 cups)
- 1 cup heavy cream
- 1/2 cup whole milk
- 1 cup sugar, divided
- 4 large egg yolks
- Equipment: an ice cream maker
- Bring purée, cream, milk, and 3/4 cup sugar to a simmer in a heavy medium saucepan over medium heat, stirring until sugar has dissolved.
- Whisk together yolks and remaining 1/4 cup sugar in a bowl, then slowly add hot milk mixture, whisking to combine. Return mixture to saucepan and cook over medium-low heat, stirring constantly with a wooden spoon, until custard is slightly thickened and registers 170 to 175°F on an instant-read thermometer (do not let boil). Immediately strain through a fine-mesh sieve into a metal bowl.
- Chill, uncovered, until cool or quick-chill by setting bowl in an ice bath and stirring occasionally until cold. Refrigerate, covered, until very cold, at least 6 hours.
- Freeze custard in ice cream maker, then transfer to an airtight container and put in freezer to firm up, about 2 hours.