Pistachio Gelato — Sicily's nutty, olive-green gelato

i. Origin & history

Pistachios are not native to Italy. They originated in Central Asia and Iran, were known to the Romans, and are generally thought to have become established in Sicily during the period of Arab rule from the ninth to the eleventh century, when many new crops arrived on the island. They found an ideal home on the volcanic slopes of Mount Etna, where they grow in black lava soil, often clinging to rocky terraces where little else will grow.

The town of Bronte, on Etna's western flank, is the centre of that cultivation. The Pistacchio Verde di Bronte has EU protected designation of origin (PDO) status and is famous for its intense flavour and deep green kernel beneath a purplish skin. The trees in Bronte are traditionally harvested only every other year, in odd-numbered years, letting them rest in between; the harvest is small and laborious, and the nuts are among the most expensive in the world, nicknamed 'green gold'.

Sicily also has one of the oldest frozen-dessert traditions in Europe, built on the snow of Etna that was gathered and stored for summer use (see granita). As gelato developed in Italy from the seventeenth century, and especially in the twentieth, pistachio became one of its most loved flavours. In Sicily, gelato is often eaten in a brioche bun for breakfast or as a summer snack, and pistachio is the island's signature.

Gelato differs from ice cream in three ways: it contains more milk and less cream, so it is lower in fat; it is churned more slowly, so it contains less air and is denser; and it is served a few degrees warmer, so it is softer and its flavour comes through more strongly. Traditional Sicilian gelato is often made without eggs, thickened instead with a little starch.

ii. Why real pistachio gelato is not bright green

The colour of pistachio gelato is the quickest guide to its quality. Pure pistachio paste, made by grinding roasted or blanched pistachios, mixed into a white milk base gives a soft, muted green with a hint of brown — the colour of an olive or khaki. Vivid, minty green gelato almost always contains colouring, and often far less pistachio, sometimes boosted with almond paste and flavouring.

The flavour depends on the proportion of nut. Good pistachio gelato contains 10–15 per cent pure pistachio paste by weight. That much nut fat changes the texture: pistachios are rich in oil, which makes the gelato dense and creamy, so the base needs less cream than a plain gelato would. Too much paste makes the gelato heavy and slightly greasy; too little, and it tastes only faintly of nuts.

The Sicilian base used here is thickened with cornflour instead of egg yolks. Starch binds the water in the milk, reduces ice crystal formation and gives a clean, light texture that lets the pistachio dominate; egg yolks would add their own flavour and richness. A little dextrose or milk powder helps keep the gelato soft and scoopable straight from the freezer.

Pistachio paste quality matters. Look for paste made from 100 per cent pistachios, ideally Sicilian. Many 'pistachio creams' sold in jars are sweetened spreads containing sugar, oil and sometimes only 30–40 per cent pistachio; they make a sweeter, less intense gelato. You can make your own paste by blending skinned pistachios until smooth.

iii. Ingredients

Makes 8 servings · scroll the side panel to adjust

• 600 ml whole milk
• 150 ml double cream
• 130 g caster sugar
• 30 g dextrose or skimmed milk powder
• 25 g cornflour
• 1 pinch salt
• 150 g pure, unsweetened pistachio paste
• 30 g shelled pistachios, chopped, to serve

The single most important ingredient is the pistachio paste; buy 100 per cent pistachio paste, preferably from Bronte, or make it by blanching 200 g shelled unsalted pistachios for one minute, rubbing off the skins, drying them in a low oven and blending until smooth and runny. Dextrose is less sweet than sugar and lowers the freezing point, keeping the gelato soft; skimmed milk powder improves body instead. A pinch of salt brings out the nuttiness. For a richer, egg-based northern Italian style, replace the cornflour with 4 egg yolks and cook the custard to 82 °C.

iv. Method

1. Whisk the sugar, dextrose, cornflour and salt together in a saucepan, so the cornflour is evenly dispersed.
2. Gradually whisk in the milk and cream until smooth.
3. Heat over a medium heat, stirring constantly, until the mixture thickens slightly and reaches 85 °C, or just comes to a gentle simmer; it should lightly coat the back of a spoon. Cook for 1 minute more.
4. Take off the heat and whisk in the pistachio paste until completely smooth; a stick blender gives the best result.
5. Pour into a bowl, set it over iced water to cool quickly, then cover and refrigerate for at least 4 hours, or overnight, so the flavour matures.
6. Whisk the base well, then churn in an ice-cream maker according to the manufacturer's instructions, usually 20–30 minutes, until thick and creamy.
7. Transfer to a chilled container and freeze for 1–2 hours to firm up. Let it soften for 5–10 minutes at room temperature before scooping, and sprinkle with chopped pistachios.

v. Tips & common mistakes

• Use pure paste, not sweetened cream. Sweetened pistachio spreads make a cloying gelato with a weak nut flavour.
• Do not expect bright green. Natural pistachio gelato is olive-green. Resist the temptation to add colouring.
• Mature the base overnight. Resting improves the texture and lets the pistachio flavour develop fully.
• Blend thoroughly. Pistachio paste can leave fine grains; a stick blender makes the base perfectly smooth.
• Serve it softer than ice cream. Gelato is best at about −12 °C. Straight from a home freezer it is too hard and tastes muted.
• Eat it within a week or two. Without commercial stabilisers, homemade gelato slowly forms larger ice crystals and becomes icy.

vi. Variations

Pistachio stracciatella drizzles melted dark chocolate into the gelato in the last minute of churning, forming fine chocolate flakes. Salted pistachio gelato adds a little more salt for a savoury edge. In Sicily, gelato is often served in a brioche, and pistachio is also used in semifreddo, cannoli cream and the layered ice-cream cake spumoni, where it forms the green layer.

Pistachio is a favourite well beyond Italy: Persian bastani combines saffron, rose water and pistachios, and Indian kulfi is often studded with them. Other Italian frozen desserts include the chocolate-coated tartufo and Sicilian granita; for a different nut-based ice cream, try black sesame ice cream.

vii. Serving & storage

Pistachio gelato is served in small scoops or with a spatula, in a cone or a cup, slightly softened. In Sicily it is eaten in a brioche or with a glass of granita, and it pairs well with chocolate desserts, almond biscuits and fresh fruit such as figs or apricots.

Store it in an airtight container with a piece of baking paper pressed onto the surface to prevent ice crystals forming. Homemade gelato is best within a week and keeps for up to two weeks in the freezer, but the texture gradually becomes icier. Soften it in the refrigerator for 10–15 minutes before serving.

ix. More from Italian

• Granita — Sicilian ice
• Spumoni — layered Neapolitan ice cream
• Tartufo — ice-cream truffle
• Bastani — Persian saffron ice cream
• Black Sesame Ice Cream — nutty Japanese ice cream
• Rose Pistachio Cake — fragrant nut cake