Trattoria Al Graspo. As I recall, they don’t take cards, so make sure you have cash with you. It was something like 30€ per head, but that was a few years ago. Once you’ve been, it will be somewhere you’ll be telling people about for years. And don’t turn anything down, just get stuck in. Although you might not want to look too closely at what you’re about to shove in your gob!