- 6 cups whole milk
- 8 large egg yolks
- 1 1/4 cups sugar
- 1/2 cup cornstarch
- 1 teaspoon pure vanilla extract, divided
- 1/2 teaspoon pure almond extract
- 2 drops green food coloring
- 1/2 cup unsweetened cocoa powder (not Dutch-process)
- 2/3 cup whole blanched almonds, toasted and coarsely chopped
- 1/2 cup unsalted shelled pistachios, toasted and coarsely chopped
- Equipment: an ice cream maker
- Bring milk to a simmer in a 4-quart heavy saucepan over medium heat. Whisk together yolks, sugar, cornstarch, and a pinch of salt in a bowl. Whisk in milk, then transfer mixture to saucepan.
- Bring to a boil over medium heat, whisking constantly, then boil, whisking constantly, 2 minutes. Immediately strain through a fine-mesh sieve into a clean bowl. Divide custard among 3 bowls. To make almond base, whisk 1/2 teaspoon vanilla into 1 bowl; for pistachio base, whisk almond extract and food coloring into another bowl; for chocolate base, whisk cocoa and remaining 1/2 teaspoon vanilla into third bowl.
- Cool to room temperature, stirring occasionally. Chill custards, surfaces covered with parchment paper (to prevent a skin from forming), until cold, at least 6 hours.
- Freeze each custard in ice cream maker, 1 batch at a time (white, then green, then brown). Fold almonds into vanilla custard, then fold pistachios into green custard. Transfer to a shallow 2-quart container or 3 smaller containers and put in freezer to firm up, about 4 hours.