Pesto is the bright-green uncooked sauce of Liguria in north-west Italy, made by pounding fresh basil leaves with garlic, pine nuts, coarse salt, hard grating cheese and olive oil to a fragrant green paste. Herbaceous, garlicky, nutty and rich, it is the classic dressing for trofie and trenette pasta and, in its full form, pesto alla genovese — the pesto of Genoa.