Pesto alla genovese is a raw sauce of basil, garlic, pine nuts, hard cheese, olive oil and salt, pounded in a mortar. It is Liguria's great contribution to the world's pasta bowls.
What it is¶
Pesto is an uncooked sauce made by crushing fresh basil leaves with garlic, coarse salt and pine nuts, then working in grated hard cheese and olive oil until it forms a loose, glossy green paste. The name comes from the Genoese verb pestâ, Italian pestare, "to pound" — the same root as pestle — and in its home city the word on its own means this basil sauce. Elsewhere in Italy pesto is used more loosely for any pounded sauce, which is why you will meet pesto trapanese, pesto rosso and a supermarket shelf of "pestos" made from kale, rocket and sun-dried tomato.
Origins¶
Ligurians have pounded garlic, herbs and cheese together for centuries; an older sauce called agliata, garlic crushed with vinegar-soaked bread, was a staple of Genoese sailors. Basil, however, arrived in the recipe late. The first printed recipe usually cited for basil pesto appears in Giovanni Battista Ratto's La Cuciniera Genovese of 1863, which calls for basil (or marjoram and parsley when basil is not available), garlic, Dutch cheese and Parmesan, and pine nuts, pounded in a mortar with a little oil.
It spread worldwide in the 1980s, when food processors and jars made it a store-cupboard staple. The local version has since been codified: Genoa's Consorzio del Pesto Genovese sets out a traditional recipe, and Basilico Genovese — small-leaved, mild, without the minty note of larger basils — has had protected (DOP) status since 2005.
What goes in it¶
| Component | Role |
|---|---|
| Basil (young, small leaves) | The body and perfume; young leaves are sweeter and less minty |
| Garlic | Pungency; traditionally one or two cloves per large bunch, not a whole head |
| Pine nuts | Richness and a faint sweetness; they also help the emulsion |
| Parmigiano Reggiano | Savoury depth and salt |
| Pecorino (often Fiore Sardo) | Sharper, saltier, sheepy edge |
| Ligurian extra virgin olive oil | Binds the sauce; the Riviera oils are mild and fruity, not peppery |
| Coarse sea salt | Seasoning, and grit that helps the pestle tear the leaves |
📌 Not strictly vegetarian
Parmigiano Reggiano and most traditional pecorino are made with animal rennet, so classic pesto is not vegetarian. Use a vegetarian hard cheese made with microbial rennet if that matters.
Flavour¶
Good pesto is sweet, fragrant and gently pungent, with a clean basil perfume, a savoury depth from the cheese and a buttery roundness from the nuts. It should not taste raw or harsh. Bitterness usually comes from bruising and overheating the leaves (a hot food-processor blade does both), from a peppery Tuscan-style oil, or from too much garlic.
How to use it¶
- With pasta. The Genoese pairings are trofie (short hand-rolled twists) and trenette (flat, linguine-like ribbons), often cooked in the same pot as sliced potato and green beans. Loosen the pesto with a spoonful of the pasta water and toss off the heat — never cook it, or the basil turns khaki and the cheese strings.
- In soup. A spoonful stirred into minestrone alla genovese at the table.
- Beyond pasta. Gnocchi, grilled courgettes and aubergine, new potatoes, tomatoes and mozzarella, a dressing loosened with lemon, a swirl on white-bean soup.
Making it at home¶
Serves 4 (with 400 g pasta) · 20 minutes by mortar; 5 by processor
You need
- 50 g young basil leaves (from about 3 large bunches), washed and patted completely dry
- 1 small garlic clove, peeled
- ½ tsp coarse sea salt
- 25 g pine nuts
- 35 g Parmigiano Reggiano, finely grated
- 15 g pecorino (ideally Fiore Sardo), finely grated
- 80–100 ml mild extra virgin olive oil
Method
- Pound the garlic with the salt in a mortar to a creamy paste.
- Add the pine nuts and pound until broken down but not oily.
- Add the basil a handful at a time, grinding with a circular motion against the side of the mortar rather than hammering, until the leaves break down to a bright green paste.
- Work in both cheeses, then trickle in the oil slowly, stirring with the pestle, until the sauce is thick but spoonable.
- Processor method: chill the bowl and blade, pulse the garlic, salt and nuts, add basil and pulse briefly with half the oil, then stir in the cheese and remaining oil by hand. Pulse in short bursts so the blade does not warm the leaves.
Variations¶
- Pesto trapanese (Sicily): almonds, raw tomato, basil, garlic and pecorino, pounded together — a legacy of Genoese ships calling at Trapani, so the story goes.
- Pistou (Provence): basil, garlic and olive oil, traditionally without nuts; cheese is optional and disputed. It is stirred into soupe au pistou.
- Pesto rosso: sun-dried tomatoes with basil, nuts and cheese.
- Walnut or almond pesto: a cheaper or allergy-conscious swap for pine nuts; walnuts are slightly bitter, so add a little extra cheese.
- Wild garlic pesto: wild garlic leaves replace both basil and garlic in spring; it is punchy, so use less.
Buying and storing¶
Jarred pesto is pasteurised and sealed, and keeps unopened for months; once opened treat it like fresh. Homemade pesto keeps 3–4 days in the fridge in a small jar with a film of oil on top to limit browning. For longer storage freeze it — in ice-cube trays is convenient — ideally before adding the cheese, which can be stirred in after thawing.
⚠️ Keep it cold
Pesto is raw garlic and herbs under oil, a low-acid, low-oxygen mix in which Clostridium botulinum can grow if left warm. Never store homemade pesto at room temperature; keep it refrigerated and use within a few days, or freeze it.