Blend 1 cup toasted shelled pistachios in a food processor until a fine paste forms, with no gritty bits left. Set the paste aside so it’s ready for the custard.

Heat heavy cream and whole milk in a saucepan until steaming but not boiling, about 3 to 5 minutes. Slowly whisk the hot dairy into the beaten egg yolks with granulated sugar to prevent scrambling.

Return the mixture to the saucepan and cook while stirring until it reaches 175F. Remove promptly when thick enough to coat the back of a spoon, typically 10 to 12 minutes.

Whisk the pistachio paste into the hot custard until smooth and evenly colored. This should look glossy and cohesive after 1 to 2 minutes of whisking.

Stir in almond extract, vanilla extract, and salt, and add a drop of green food coloring if desired. Whisk until the flavor is uniform, then strain the custard through a fine strainer for extra smoothness.

Chill the strained pistachio custard in the refrigerator for 4 hours, until thoroughly cold. A skin may form—stir gently before churning if needed.

Churn the chilled custard in an ice cream maker until thickened to the texture of soft-serve, about 20 to 25 minutes. Fold in roughly chopped pistachios at the end so the pieces stay visible.

Transfer to a freezer-safe container and freeze until firm, at least 4 hours. The surface should be scoopable with a dense, creamy interior once fully set.