Drain the tomatoes, reserving the juice. Add the tomatoes and the rest of the ingredients to the leftover sloppy joe mixture, and simmer over medium heat for about 30 minutes (although simmering for longer will develop the flavors even more). Use the reserved juice from the tomatoes to thin out the sauce if needed.
Remove the bay leaves and serve.
Notes
Use as much or as little leftover sloppy joe mixture as you have to make this sauce. More sloppy joe mixture will give you a super meaty sauce, while less will give you a more tomato-based sauce.