Pesto been used for all sorts of cold sauces or dips, mostly without any of the original ingredients: arugula (instead of or in addition to basil), black olives, lemon peel, coriander, or mushrooms. In more northern countries, ramson leaves are sometimes used instead of basil. In the 19th century, Genovese immigrants to Argentina brought pesto recipes with them. A Peruvian variety, known as "tallarines verdes" (meaning "green noodles", from Italian "tagliarini"), is slightly creamier, lacks pine nuts (because of their rarity and prohibitive cost in Peru), may use spinach and vegetable oil (in place of olive oil), and is sometimes served
Bread sauce or chicken. The use of slightly stale bread is optimal, making it an economical way of using up leftover bread. The sauce is easy to make and uses readily available ingredients. Bread sauce can be traced back to at least as early as medieval times, when cooks used bread as a thickening agent for sauces. The utilisation of bread in this way probably comes from cooks wanting to use up their stale bread who discovered that it could be incorporated within sauces to make them thicker. Turkish cuisine also features a cold sauce made from breadcrumbs mixed with pounded walnuts