Heat olive oil in a large skillet over medium high heat. Add in the bell pepper and onion. Cook for 2-3 minutes. Add in the ground beef. Continue cooking over medium heat. Breaking up the meat while it cooks. Cook until the meat is completely browned, approximately 5 minutes. 

Once the meat is browned and the onion and peppers are tender, add in the garlic. Cook an additional 30 seconds. 

Add in the tomato paste, Worcestershire sauce, tomato sauce, ground mustard, molasses, apple cider vinegar, chili powder, paprika, salt and pepper. Stir to coat the meat. 

Allow the meat to cook in the sauce for about 5 minutes. During this time prepare the hamburger buns by spreading a little butter on the insides and toasting in a skillet. 

Serve the sloppy joes warm. 

Cook the ground beef, bell pepper and onion in a large skillet. Drain the grease. Add the meat mixture to a slow cooker. 

Add in the remaining ingredients. Stir to coat the meat mixture. 

Cook on LOW for 4-6 hours or cook on HIGH for 2-3 hours.