From America's Test Kitchen Season 3: Hearty Soups
Split pea soup tends to show up on the home cook’s menu only when the previous meal (usually a holiday celebration) featured a big ham—and the leftovers are begging to be made into soup. We wanted a recipe for an old-fashioned ham and split pea soup that could be made anytime, with a readily available cut of meat that would also provide enough meat for the soup. Ham stock is essential for this soup, and we found that you can get it with a picnic shoulder, a small, inexpensive cut that adds great flavor and provides plenty of meat for the soup and some leftovers too. As for soaking the peas beforehand, a step called for in many soup recipes, we found it wasn’t necessary; they were easy enough to cook in the ham stock. Our vegetables, on the other hand, benefited from a sauté in a separate pan. We started out wanting a one-pot operation, but found that caramelized vegetables gave this straightforward soup a richness and depth of flavor that had been missing from traditional versions—it was well worth the time spent washing an extra pan. Finished with a splash of mildly sweet balsamic vinegar, this rich and meaty split pea soup was now perfectly balanced.
Use a small 2 1/2-pound smoked picnic portion ham if you can find one. Otherwise, buy a half-picnic ham and remove some meat, which you can save for use in sandwiches, salads, or omelets (see illustrations below). If you like caraway, see related recipe. The finished soup will continue to thicken as it stands but can be thinned with some water when reheated. To cut 45 minutes off the cooking time of the soup, simmer the ham 1 1/2 hours, then add the split peas to the pot. When the ham is tender, after about 45 minutes more of simmering, remove it and shred.