Heat oil in a skillet over medium heat. Add celery and onion; cook and stir until onion is translucent, 5 to 7 minutes. Add cooked ham bone meat, lima beans, and diced ham. Reduce heat and simmer, adding additional water as needed, until soup is thickened to desired consistency, about 90 minutes.
Made with a ham bone, dried white beans, chopped carrots, celery, onions, and garlic, chicken stock, and fresh thyme, this ham soup recipe takes minutes to assemble in a slow cooker. Then it simmers all day, producing a rich and flavorful soup with hardly any effort. For best results, choose a large, meaty ham bone.