The only time I was ever confronted with a huge portion was in a little pizzeria in a back street in Naples, just up from the Duomo. I'd seen in an Italian cookery book that, once in one's life, one ought to go to Napoli and endure a pizza fritta. So here was my chance. I knew as soon I'd ordered the damn thing that there a challenge on. The look in the waiter's eye was a combination of scepticism and dare. When it arrived I could scarcely believe it. It was a pizza that had been folded over, was six inches thick in the middle, eighteen inches long - and deep fried. I couldn't help noticing the smug expression on the waiter's face as he slapped the thing down in front of me.   Eat that if you can, Inglese, he seemed to hint. But, begod, I did it. I was too stuffed to do anything else that day, but at least I'd found martyrdom.