Sprinkling the onions with salt as they cook not only seasons them, but extracts some of the water and intensifies their flavor. Keep the water hot before adding it to the soup, as described below, and you won’t interrupt the cooking—it will flow smoothly from start to end. Remember this when braising meats like the short ribs on page 218, or when making risotto. You can use the method outlined below—bringing the beans to a boil, then soaking them in hot water for an hour—anytime you want to cook beans without soaking them overnight, or anytime you’ve forgotten to soak them a day in advance. It works especially well here because, by soaking the pork along with the beans, you kill two birds with one stone. (I soak the dried or cured pork to remove some of the intense curing-and-smoking flavor. If you like it intense, just rinse the pork under cold water before adding it to the soup.)
This recipe makes quite a bit of soup. If you plan to refrigerate or freeze some for future use, do so before you add the pasta—the pasta will continue to absorb liquid and swell after cooking, making for overcooked pasta and a too-thick soup. Reduce the amount of pasta called for in the recipe according to how much of the soup you plan to serve immediately.