The Provençal love to quarrel about soupe au pistou. Mainly, they're squabbling about whose version is best. To an outsider like me, however, this soup in any configuration is one of summer's finest dishes.
Typically added to a vegetable-rich soup, pistou has had a long history. The Roman poet Virgil described a sauce made by crushing herbs in a mortar with garlic, salt and olive oil. Over time, the sauce morphed into the heady Genoese pesto, which then morphed into pistou in Nice.
Making my pistou starts with adding tomatoes and olive oil to basil, garlic and salt, then crushing the mixture in a mortar with a pestle until it's smooth. (In the Provençal dialect, pistou means "pounded.") The pistou is then stirred into the soup, amplifying the flavors of both.
The Provençal also spend a lot of time discussing versions of the soup. Traditionally, it includes a homemade broth, fresh white beans, green beans, potatoes and macaroni. A recipe by Patricia Wells adds pumpkin; one by Richard Olney calls for carrots. Cooks in Provence often vary the pasta, too (some use vermicelli). Robert Lalleman, the chef at the esteemed Auberge de Noves in Avignon, enriches his recipe by sautéing pasta in butter before mixing it into the soup.
What follows is a classic recipe for the sauce plus two variations on the soup—one I recently concocted with pancetta and the other, the first soupe au pistou I ever loved.