Pesto alla genovese is never cooked and never blended hot: it is a raw emulsion in which olive oil binds basil, nuts and cheese. Made properly, it stays vivid green and fragrant. The keys: quality ingredients, young basil, and a mild olive oil that does not overpower.
Ingredients
- 50 g fresh basil leaves (small, Genoese type)
- 15 g pine nuts
- 1 small garlic clove (germ removed)
- 30 g freshly grated Parmigiano Reggiano
- 20 g grated Pecorino (Fiore Sardo)
- 70–100 ml mild extra virgin olive oil (ideally Ligurian)
- Coarse salt
Step-by-step method
- Pound the garlic. In a marble mortar, crush the garlic with a few grains of coarse salt into a paste.
- Add the pine nuts. Work them in until creamy.
- Basil. Add the washed, well-dried basil in small handfuls, crushing with a rotating motion against the sides of the mortar — never pounding. The basil should release a bright green liquid.
- Cheeses. Work in the Parmesan and Pecorino to a cream.
- Olive oil. Pour in the extra virgin olive oil in a thin stream, stirring, to a smooth, glossy sauce. Taste and adjust salt.
- Serve. Loosen with a spoon of pasta cooking water, off the heat. Never boil it.
Variation
Blender version (no oxidation): chill the bowl and blades 10 minutes. Pulse in very short bursts so the blades don't heat up (heat blackens basil). For lasting green, blanch the basil 5 seconds then shock in ice water before blending. Finish the oil by hand.
The role of olive oil
Olive oil is more than a binder: it carries the basil aroma and rounds the garlic. Choose a mild, fruity extra virgin (very bitter, peppery oils crush the basil). A delicate Ligurian oil is the classic match.
Tips for success
- Young, dry basil: water dilutes and oxidises pesto.
- Work cold, never hot: cooked pesto turns grey and bitter.
- Mild oil, not robust, to let the basil speak.
- Dress pasta off the heat with a little cooking water.
- For trofie, trenette or gnocchi: add potatoes and green beans, Genoa-style.
Variations
- Nut-free: replace pine nuts with a little more oil (different texture).
- Keeping pesto: without cheese (add when serving) it stores and freezes better.
How to serve it
Serve pesto raw over hot pasta (trofie, trenette, linguine) loosened with cooking water, over gnocchi, stirred into minestrone off the heat, or on toast. Never cook it: heat destroys the aroma and colour.
Storage
In the fridge 3–4 days in a jar, topped with a thin layer of olive oil to seal it from air. It freezes well, ideally without the cheese (add when serving).
Frequently asked questions
What are the real ingredients of pesto alla genovese?
Basil (ideally Genoese), pine nuts, garlic, Parmigiano Reggiano, Pecorino, extra virgin olive oil and coarse salt. Nothing else: no cream, no cashews, no lemon in the traditional recipe.
Mortar or blender for pesto?
A marble mortar gives the best result because it crushes without heating. A blender works if you chill the bowl and pulse in very short bursts so blade heat doesn't oxidise the basil.
Why does my pesto turn grey?
Oxidation: wet basil, blade heat or air exposure. Dry the basil well, work cold, and cover the pesto with olive oil. Blanching the basil for 5 seconds fixes the colour.
Which pasta with pesto?
Ligurian trofie and trenette (or linguine), often with potatoes and green beans cooked in the same water. Gnocchi work very well too.
Can you freeze pesto?
Yes, ideally without the cheese, in an ice-cube tray or a jar topped with oil. Add the Parmesan and Pecorino when serving.