This recipe can be prepared several different ways. Always cook the bacon first. I like to chop it into about 1" pieces and cook until it's almost (but not quite) crispy. Then I add the onion finely chopped and caramelize it in the bacon grease. You can use leftover ham and simply add the other ingredients and cook over low heat for an hour or so. Or, you can slow roast the ham separately and then add the beans and other ingredients. You do not want to cook beans from a jar for too long or they will simply fall apart and you'll have more of a soup with chunks of ham in it. If you use dry beans, you could cook the ham with the beans. When I prepare the recipe this way, I prefer to use a pressure cooker. If you do not have a pressure cooker, you will need to cook the beans and ham for several hours on low heat. Perhaps use a crockpot overnight.