Panzanella is Tuscany's great summer salad—a room-temperature assemblage of soaked stale bread, ripe tomatoes, red onion, cucumber, basil, and olive oil that is simultaneously one of Italy's most ancient dishes and one of its most frequently botched outside its homeland. The dish dates to at least the 14th century (Boccaccio mentions a version) and represents the ultimate expression of Tuscan waste-nothing philosophy: yesterday's bread, today's garden vegetables, and the ever-present olive oil combine into a dish of startling freshness and substance. The canonical preparation soaks chunks of stale pane toscano in cold water for 10-20 minutes until softened but not mushy, then squeezes them firmly to remove excess moisture. The bread is crumbled into a bowl and tossed with chopped ripe tomatoes (which release juice that further moistens the bread), thinly sliced red onion (soaked in cold water to reduce harshness), cucumber, and torn fresh basil. The dressing is simply red wine vinegar, extra-virgin olive oil, salt, and pepper. The assembled panzanella rests for at least 30 minutes before serving—this rest is critical, allowing the bread to absorb the tomato juices, vinegar, and oil, melding the flavours into a unified whole. The bread should be moist but not slimy, with identifiable pieces providing textural interest. Panzanella is strictly a summer dish—it requires dead-of-summer tomatoes at their peak of flavour and juiciness. The unsalted Tuscan bread is again essential: its neutral flavour and sturdy crumb absorb the dressing without dissolving, and its lack of salt allows the tomatoes and seasoning to provide all the salinity.
Soak stale unsalted Tuscan bread, then squeeze out excess water. Combine with peak-summer tomatoes, red onion, cucumber, basil. Dress with red wine vinegar and olive oil. Rest at least 30 minutes before serving. Serve at room temperature—never cold.
The quality of the tomatoes makes or breaks panzanella—don't attempt it with winter tomatoes. Red onion soaked in ice water for 10 minutes loses its harshness while retaining crunch. Some Tuscans add anchovies or capers for salinity. Let the salad sit at room temperature, covered, for 30-60 minutes for best flavour integration.
Using fresh bread (too soft, dissolves). Making it outside tomato season. Over-soaking the bread (becomes mush). Under-resting (flavours don't meld). Serving cold from the fridge. Adding too many extra ingredients (keep it simple).
Pellegrino Artusi, La Scienza in Cucina; Giuliano Bugialli, The Fine Art of Italian Cooking