Heat the oil in a sauté pan over medium heat. Add the onion, celery and carrot and cook until they begin to soften but not brown, about 2 to 3 minutes.

Add the ground beef and garlic, and cook while breaking up the meat with a spatula. Season with the salt and pepper. Continue to cook until the meat has browned all the way through. Drain the excess fat and discard.

Add the tomato sauce, honey, chili powder, vinegar, mustard, and cinnamon (if using) to the pan and simmer over low heat until the sauce thickens, about 10 to 15 minutes. Serve warm with whole-wheat buns and some yummy vegetables on the side. Enjoy!