Here, a cold sauce is used with hot pasta.
Cold sauces are also combined in Italy with hot main courses and even desserts.
Panzanella is the traditional Tuscan bread salad, which mixes crumbled bread with fresh tomatoes, basil, onions, and a dressing made with olive oil and vinegar. In Siena, where this recipe hails, the uncooked sauce has been adapted to pasta and fresh arugula added. Coarsely chop the onion and put it in a bowl of cold water for 30 minutes. Cut the tomatoes into 1-inch pieces without removing the seeds and put them in a glass or ceramic bowl. Drain the onion and place it over the tomatoes.