I first encountered pistou in Julia Child’s Mastering the Art of French Cooking Vol 2.
Pistou, a Provençal purée of fresh garlic and basil, is stirred into sautéed aubergines that have simmered with tomatoes, peppers, and onions, making a dish reminiscent of that famous Mediterranean medley, ratatouille, but much easier to produce.
It’s only easier to produce because Child’s recipe for ratatouille is so unnecessarily complicated and involved. Pistouille, for decent ordinary people, is simply ratatouille served with pistou sauce. Traditionally, pistou is made with olive oil and that recipe can be found with a simple Google search. This variation was taught to me by a Niçoise man by the name of JR who I met while traveling.