This is a good moment for beans. The market is full of them, including thick or skinny string/French beans to boil or stir-fry, plus their yellow and purple variants; limas; cranberry and other shelling beans in their semi-dried pods - good for eating now or for freezing (these are the sorts of beans you will buy fully dried in a while and through the winter); and my current crush, flat beans, a.k.a. romano beans (and in the UK runner beans - though ours are a little gnarlier).
They have a lot of flavor - not dissimilar to that of the usual string beans (French beans in the UK) - and can withstand a lot of cooking. In fact, they need a lot of cooking, because trying to eat them after too-brief boiling or steaming is an exercise in, well, exercise: they'll give your teeth and jaws an unwanted workout. Happily, they also taste better when cooked with tomatoes, aromatics and plenty of oil - as an Italian might cook them, which is how I do it, too. It amounts to braising and can be done ahead of time. ("Braising" makes this sound like an all-day project, but these are beans, not lamb shanks, so they actually take only half an hour or 40 minutes including all preparation.)
Two pounds (a kilo) of flat beans will serve six or eight people as a side dish; with boiled potatoes dressed with olive oil and lots of salt, they can also be a satisfying dinner for four to six. For that quantity, I started by blanching and peeling, then dicing, a generous pound (500 g) of ripe tomatoes - on that day it was a mixture of varieties, some big, some small; use the best late-summer tomatoes you can find. No, you don't have to peel them.
I salted the tomatoes to start their juices flowing and turned to the aromatics: I sliced two medium onions (one red and one white, because that's what came to hand; use whatever onions you have in the house) and put them into a deep frying pan (or shallow casserole) with salt and a generous amount of olive oil over medium-low heat. To this I added two big cloves of garlic, sliced or chopped; four or five leaves of sage, torn into pieces; and two dried Calabrian chilies, seeded and cut into 3/8-inch (1-cm) lengths. Other chilies would be fine, though my preference would be for dried, not fresh ones; the quantity will depend on how hot they are and on your tastes: the heat should be palpable but only as a background element.
While these aromatics sweated, Jackie and I trimmed the ends off the previously washed beans and cut the larger ones in half or thirds - one titanic specimen needed quartering. Aim for lengths of two to three inches (5 to 8 cm). As we worked, I kept an eye on the onions to make sure they didn't brown. When they were soft, I raised the heat to medium and added the beans and tomatoes, using tongs to combine everything, then covered the pan. At this stage, the lid could not be put on tightly because the heap of ingredients was taller than the pan, but as the beans softened they soon subsided.
The tomatoes were wonderfully juicy, and the beans were damp from washing, so there was enough braising liquid in the pan, but use your judgment about adding a little water or vegetable stock; no more than a quarter cup (60 ml) of extra liquid is likely to be needed. Make sure you've used enough salt.
Keep the heat at the low end of medium, and keep the lid on the pan except when you're stirring the beans and checking on progress, which you should do every five minutes or thereabouts. The beans should be tender - indeed, soft - after 20 minutes and will have lost their market-green color. Yet, if you dare, you can cook them ten minutes longer; I know that's a hard sell for cooks who usually work hard to retain bright colors and crisp textures in their vegetable dishes, because these beans bear all the markers of being overcooked.
So as not to scare the horses, I've taken to using the term "hypercooked" instead, but there's really nothing frightening here. With the savory, almost meaty tomatoes, aromatic onions and rich olive oil, and because of their inherent virtues, these soft, pallid beans are as delicious as they come. So pounce on them next time you're at the market: they won't be around too much longer.
Note that, as with so many Italianate dishes, the beans can be served hot or tepid; they also lend themselves well to reheating if you have any left over. The leftovers can sometimes benefit from a squirt of lemon juice and/or a strewing of crunchy salt.