The water used to cook a pot of beans is really liquid gold, infused with aromatics and thickened with starch from the beans. It makes perfect sense to give the cooking liquid a second life as the broth for the soup (and save the trouble of rinsing and draining). The ham hock will season the broth and the beans as they cook; you won’t need additional salt once they are done. Instead of cooking the kale and carrots in the soup, give them a quick sauté and stir them in at the end so they retain their vibrancy.
How to Make It
Place beans in a large bowl or container; cover with cold water to 4 inches above beans. Let the beans stand at room temperature overnight; drain.
Bring drained beans and 10 cups water to a boil in a large Dutch oven, skimming surface occasionally. Add 1/4 cup oil, thyme, bay leaves, onion, and ham hocks. Reduce heat to low; cover, and simmer 30 minutes, stirring occasionally. Stir in 1 teaspoon salt; cover, and simmer 1 hour and 45 minutes or until beans are tender.
Remove pan from heat. Remove thyme, bay leaves, and onion; discard. Place ham hocks on a cutting board. When cool enough to handle, remove meat from bones; discard bones and any fat and gristle. Shred ham into bite-size pieces. Place 3 cups bean mixture in a bowl; mash with a fork. Stir ham, mashed beans, and remaining 3/4 teaspoon salt into remaining bean mixture.
Heat remaining 2 tablespoons oil in a large skillet over medium-high. Add carrots; cook 4 minutes or until slightly tender. Add garlic; cook 1 minute. Add kale; cook 2 minutes or until wilted, stirring occasionally. Stir carrot mixture into soup.