Insalata di Pomodori, Cetrioli, Cipolla e Basilico

The salad tomatoes we use in Northern Italy are usually underripe, even partly green, a practice that shocks most visitors from America. I have never known anyone, however, to have suffered from eating them. The reason we choose tomatoes that are not fully ripened is that we prize their firmness and slightly tart, sprightly taste. On the other hand, in Central and Southern Italy, from Tuscany to Sicily, it is the tender, sweet, well-ripened tomato, the kind Northerners would be more likely