Fettuccine alla gricia, a common pasta dish in Rome, has four ingredients: the noodles, olive oil, bits of cured pig's cheek, and grated cheese. Most trattorias offer it. It's not innovative, nor is it usually presented with much elegance. It's simply an oily plate of flat, yellow noodles with some reddish brown bits of guanciale and a shower of pecorino. The pleasure it gives is hard to describe. The word delicious somehow seems too refined and cerebral, tasty insufficiently hyperbolic. Scrumptious is close, but kind of pretentious. Anyway, a good alla gricia is lipsmackingly, profoundly pleasurable to eat.
There's a difference between eating and dining. In Rome, you eat. By eating, I mean the straightforward, carnal pleasure of gnawing things that taste good. A perfect example would be another common speciality: abbacchio scottadito, which is grilled very young lamb sauced with a lemon wedge. There's usually a rib, a bit of shoulder or leg, and a chop. (Incidentally, Urdu speakers call a chop a “champ,” which has always struck me as charming, and oonomatopoetic of lipsmackingness.) Abbacchio scottadito is variously salty, gamy, fatty, and cartilagenous. It tastes extremely, intensely lambish. Impossible not to chew the bones.
Not that you can't dine in Rome: at La Rosetta, Rome's most celebrated fish restaurant, you can wear your Lanvin suit, sit with the multinational haute-bourgeoisie, and have a spaghetti with seafood that costs forty-two euros. But I had a superb (superb!) spaghetti alla vongole for eight euros at a random neighborhood restaurant. By the way, you can make this at home very easily: fry a tiny bit of minced garlic, add some white wine and the smallest clams you can find, cover till they open, and mix with some high-quality pasta (I recommend Martelli, if you can find it; I can't anymore) and a bit of chopped flat-leaf parsley. End of story. But try getting dime-sized little vongole outside of Italy that are as fresh and sweetly saline.