Pistou is Provence’s answer to Genoese pesto—a raw paste of fresh basil, garlic, olive oil, and (optionally) Parmesan, pounded in a mortar until it becomes a vibrant, emerald-green sauce of extraordinary aromatic intensity. While it shares a common ancestor with pesto (both names derive from the Latin pistare, to pound), pistou is distinguished by several critical absences: no pine nuts, no butter, and in the strictest Provençal tradition, no cheese. These omissions produce a purer, more intensely basil-forward preparation that is lighter and more versatile than its Ligurian cousin. The technique demands a marble mortar and wooden pestle: two cloves of garlic are pounded with coarse salt to a smooth paste, then the basil leaves (60-80 large leaves from Provençal petit basilic, never the large-leafed Genovese variety) are added in batches, pounded to a rough paste, and olive oil is drizzled in while continuing to work the mortar. The pounding action—a grinding, rotating motion—ruptures the basil’s cell walls differently than a blade, releasing the aromatic compounds more completely and producing a paste that tastes more intensely of basil than any blended version. The finished pistou should be thick, rough-textured, and brilliantly green. Its primary application is stirred into Soupe au Pistou at the table, but it also adorns grilled vegetables, pasta, fish, and eggs. The paste must be used within hours of preparation—it oxidises rapidly, turning brown and losing its ethereal freshness.
Pound in a mortar—blending with a machine oxidises the basil and produces a different, inferior flavour. Use Provençal petit basilic or sweet basil with small leaves—large-leafed varieties are coarser. Add oil gradually to create an emulsion, not a separated mixture. Use immediately or within hours—pistou does not keep. No pine nuts, no butter—these belong in pesto, not pistou.
Chill the mortar in the freezer for 10 minutes before starting—the cold stone helps prevent the heat from friction oxidising the basil during pounding. For a richer version (closer to pesto but still Provençal), add 30g finely grated Parmesan after the basil is incorporated—this is increasingly common even in traditional households. The Provençal trick for preserving pistou’s colour for a few hours: press cling film directly onto the surface to exclude all air, and float a thin layer of olive oil over the top.
Using a blender or food processor, which heats and oxidises the basil, producing a duller, less aromatic paste. Adding pine nuts (making it pesto, not pistou). Making in advance and refrigerating, where it loses vitality within hours. Using dried basil, which bears no resemblance to the fresh herb. Not pounding the garlic to a smooth paste before adding basil, leaving sharp garlic chunks in the finished pistou.
La Cuisinière Provençale — J.-B. Reboul