All the research agreed on guanciale as a primary ingredient, though most allowed the substitution of pancetta. Franco was selling his marvelous pancetta at the Healdsburg Farm Market on Saturday, and we'd bought some, so yesterday I bought a pound of fusilli* and a few cipollini and we were all set.
One source, I forget which, allowed as how the original recipe no doubt lacked tomatos, as they weren't introduced to the New World until after Columbus's voyages (and weren't considered edible for a few decades after that). Just as I was deciding how true that could be, the same source said ditto onions, and I knew I could forget it; onions have existed in Italy since the beginning of time. (There's another controversial ingredient, which I suppress from these instructions: red pepper flakes, or, in our copy of Roma in bocca, peperoncini I think this cannot be authentic to Amatrice; it betrays the frequent Calabrese influence on Roman cooking. Another matter to research, preferably on site.)
So I followed Ada Boni, and I recommend you do the same: slice an onion (I used three good-sized cipollini) thin and cook it until soft in a couple of tablespoons of olive oil, very slowly. When the onions are soft, add five or six ounces of pancetta cut into small dice and fry them for a little while. The object here is not crispness or browning; it's cooking, sweating out the pork-fat, melding the pancetta and the onions.
(This is controversial in our house. The Contessa has an exaggerated dislike for anything she dismisses as "fat," finding it "repulsive"; she prefers her bacon quite crisp. Ah well.)
Add half a glass of white wine and cook that down; then add a pound of ripe tomatoes, or canned tomatoes. (I used a quart of the marvelous roasted tomato sauce Cook made last fall.) Salt and pepper to taste. Cook this, but not too long; pour it over the cooked pasta; sprinkle grated Pecorino on top.
We had a couple of friends over, and in all the conversation and the cheeses-before-dinner and the apéritifs and the last-minute cooking I forgot to photograph the final dish, which is a pity, because it looked wonderful. Therefor the photos above: the pancetta and onions; the tomato sauce.
We had the obligatory green salad afterward, and then, since I'd picked some black figs this morning, Deborah Madison's fine baked figs with honey and butter and cinnamon. Pastry Chef cooked the figs, and they were spectacular.
*Bucatini is the more traditional pasta for the dish, but I love the soft, wheaty fusilli made by Maestri Pastai; their twisty shape holds this sauce very nicely.