Slow cooker. Revolution. Will cook it on low for six hours, it's amazing.
Onions, mince, bacon or pancetta if I can be bothered, tomatoes, puree, red wine if I've got some, jar of bought sauce if it's in the cupboard, basically a "chuck it in the pot and see" type effort. (No peppers or other random veggies though, brolly!). Then six hours of slow simmering with the occasional stir. Job done.