Pesto genovese: seven ingredients and a mortar

Pesto takes its name from 'pestare', to pound. It is made by crushing ingredients in a marble mortar with a wooden pestle. Its ancestor is probably the 'agliata', a medieval Ligurian garlic sauce. The first printed recipe close to today's pesto appeared in Giovanni Battista Ratto's 'La Cuciniera Genovese' in 1863.

According to the Consorzio del Pesto Genovese, the real thing has just seven ingredients: Genovese basil (protected as a DOP), extra-virgin olive oil, Parmigiano Reggiano, Pecorino (traditionally Fiore Sardo), pine nuts, garlic and coarse salt. Since 2007 Genoa has hosted a World Pesto Championship, where competitors must make it by hand in a mortar.

In Liguria pesto goes on trofie or trenette pasta, and also on focaccia and in sandwiches. It's a fresh, no-cook sauce, so make it in small batches and cover it with a film of oil to keep it bright green.

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