Soak beans in enough cold water to cover them by 2 inches for 6 hours or overnight. (Alternatively, use the quick-soak method: Place beans in a large pot with enough water to cover by 2 inches. Bring to a boil over high heat. Remove from heat and let stand for 1 hour.)Advertisement
Drain the beans and place them in a slow cooker. Add onion, garlic, thyme and bay leaf. Pour in boiling water. Cook, covered, on high until beans are tender, 2 to 3 1/2 hours. Add salt, cover, and cook for 15 minutes more.
For easy cleanup, try a slow-cooker liner. These heat-resistant, disposable liners fit neatly inside the insert and help prevent food from sticking to the bottom and sides of your slow cooker.
Tip: Don't use kidney beans in this recipe; slow-cooking doesn't destroy a natural toxin in kidney beans that can cause severe digestive distress. After soaking, kidney beans must be boiled in fresh water for at least 30 minutes to render them safe to eat.