Wash the basil- Basilico genovese Dop- and let it dry on a dish towel. In a mortar, put the garlic cloves, one for every thirty basil leaves, and a few grains of coarse salt. At this point begin to grind the ingredients in the mortar, adding the basil leaves and garlic as indicated above, a little at a time, continuing to grind with a delicate, prolonged, circular motion.
When a bright green liquid begins to appear in the mixture, add the pine nuts and continue to grind, making these into a paste as well and mixing it into therest. Add the cheeses: Parmigiano Reggiano and Pecorino sardo, with the possibility of replacing them with a choice of Grana Padano and Pecorino Romano, Toscano, Sardo or Siciliano. Finally, pour in extra virgin olive oil, a drop at a time.