Brown ground turkey in a large skillet over medium-high heat. Add onions and bell pepper and cook 3 minutes or just until softened. Add garlic and cook for 1 minute longer. Drain excess fat or liquid from the meat and transfer to slow cooker.
Sprinkle salt, black pepper and flour over the meat then stir to combine. Add tomato sauce, ketchup, yellow mustard, Worcestershire sauce and tomato paste then stir until everything is evenly incorporated.
Cover and cook on low for 4–5 hours. Before serving, taste for seasoning. If the Sloppy Joe mixture needs a bit more salt, consider adding an additional dash of Worcestershire or squirt of mustard for added flavor. Serve Sloppy Joes on toasted buns topped with a little shredded cheese if desired. Enjoy!
Use ground beef or chicken for results that are just as great!