Pesto became a staple in the Ligurian culinary tradition, with each family often featuring its own pesto recipe (with slight differences to the traditional ingredients). This is the main reason why pesto recipes often differ from each other. In 1944, "The New York Times" mentioned an imported canned pesto paste. In 1946, "Sunset" magazine published a pesto recipe by Angelo Pellegrini. Pesto did not become popular in North America until the 1980s and 1990s. Pesto is traditionally prepared in a marble mortar with a wooden pestle. First, garlic and pine nuts are placed in the mortar and reduced to a cream,
Pesto by crushing garlic, salt, cheese, herbs, olive oil and vinegar together. The use of this paste in the Roman cuisine is mentioned in the "Appendix Vergiliana", an ancient collection of poems where the author dwells on the details about the preparation of "moretum". During the Middle Ages, a popular sauce in the Genoan cuisine was "agliata", which was basically a mash of garlic and walnuts, as garlic was a staple in the nutrition of Ligurians, especially for the seafarers. The introduction of basil, the main ingredient of modern pesto, occurred in more recent times and is first documented only in