Pistachio Ice-cream

Ingredients

Equipment Needed

• •Small food processor or large mortar and pestle
• •Heavy 2-quart saucepan
• •Fine-mesh sieve
• •Instant-read thermometer
• •Immersion blender
• •1½-quart ice cream machine
• •Shallow freezer-safe container

Instructions

1. 1

   Peel the pistachios

   Bring a small saucepan of water to a boil. Add the pistachios for 30 seconds, drain them, and rub away their loosened purple-brown skins while the nuts are still warm. If a few skins cling, return those nuts to the water for another 15 seconds rather than scraping at them. Pat the peeled kernels completely dry. Do not toast them; toasted pistachios taste splendid, but they turn this ice cream brown and pull it away from the source.

   Work while the pistachios are warm. Once they cool, the skins tighten again and a simple job becomes a small domestic argument.
2. 2

   Pound the nuts

   Put the peeled pistachios and sweet almonds in a small food processor. Pulse them to a fine meal, then process continuously while adding about 1 teaspoon of the measured milk drop by drop, only enough to help the blades form a close, damp paste. Scrape down the bowl often. The source calls for pounding in a mortar; the processor replaces the labour, not the result. If the paste grows warm and begins to release a shiny film of oil, chill it for 10 minutes before continuing.

3. 3

   Infuse the paste

   Bring the remaining milk just to a full boil in a heavy saucepan, watching closely so it does not climb over the rim. Remove it from the heat immediately, stir in the nut paste, cover, and leave it to infuse for 20 minutes. Keep the full infusion. This is one of the steps that is the dish, not pastry-room scaffolding: the boiled milk draws out the nuts' fragrance while the almond softens the pistachio's sharper edge.

4. 4

   Cook the crème anglaise

   Pour the cold cream into a large heatproof bowl and set a fine sieve over it. Whisk the yolks and sugar in a second bowl until smooth and slightly lighter, without beating in excess air. Reheat the infused milk until hot, then pour one-third into the yolks while whisking. Return everything to the saucepan and cook over low heat, stirring constantly across the bottom and into the corners, until the crème anglaise, the pouring custard, coats the spatula and reaches 78 to 82°C (172 to 180°F). Never let it boil. If you see tiny curds, remove the pan at once and pour the custard through the sieve into the cold cream, then blend briefly. Ça se rattrape. Large, dry curds and an eggy smell mean it has gone too far.

   Draw a finger through the custard on the spatula. When the track remains clean instead of flooding closed, the crème anglaise is ready.
5. 5

   Chill the base

   Stir the custard into the cold cream, then blend it for 20 to 30 seconds with an immersion blender so the nut oils and dairy settle into one smooth emulsion. Set the bowl over ice water and stir until thoroughly cold. Cover and refrigerate for at least 4 hours, or overnight. The base must be cold before churning or it will freeze into coarse crystals. Its colour should be a quiet, natural green, not the green of confectioner's paint.

6. 6

   Churn until supple

   Churn the cold base in a 1½-quart ice cream machine according to its directions, usually 20 to 30 minutes, until it holds soft folds and a lifted spoon leaves a firm track. Stop while it is dense but supple. Churning far beyond that point warms the bowl and can turn the cream grainy.

   If the base remains pourable after 30 minutes, the freezer bowl was not cold enough. Transfer the mixture to a shallow metal container, freeze for 30 minutes, then beat it vigorously; repeat twice before leaving it to harden.
7. 7

   Harden and serve

   Pack the churned crème glacée into a cold, shallow container, press parchment directly against the surface, cover, and freeze for 3 to 4 hours. Let it stand at room temperature for 5 to 10 minutes before scooping. You want a dense, yielding spoonful with pistachio first and almond quietly underneath. À table!

Chef Tips

• •Buy raw, unsalted pistachios with bright interiors. Roasted nuts give a deeper, browner flavour, while salted nuts make the custard nearly impossible to balance; neither produces the crème glacée described by the source.
• •Sweet almonds means ordinary edible almonds, preferably already blanched. Never substitute bitter almonds, which contain compounds that can release cyanide and are not safe replacements here.
• •No pistachio extract and no green colouring. Freshly peeled kernels, properly infused, give a quieter colour and a fuller flavour than either bottle can manage.
• •Homemade ice cream freezes harder than heavily stabilized commercial tubs. Let it soften for several minutes before serving, and dip the scoop in hot water between portions.

Advance Preparation

• •The custard base can be cooked and refrigerated up to 24 hours before churning. A long cold rest improves its texture and lets the pistachio and almond settle into one flavour.
• •Churn and harden the crème glacée up to 3 days before serving. Keep parchment against the surface and the container tightly covered so the nuts do not absorb freezer aromas.

Frequently Asked Questions

Nutrition Information

1 serving (about 150g)