In a large skillet, brown the ground beef over medium-high heat until no longer pink. Drain any excess fat and transfer the beef to a slow cooker.
Add the chopped onion, green pepper, and minced garlic to the slow cooker.
In a mixing bowl, whisk together the beef broth, Worcestershire sauce, ketchup, yellow mustard, brown sugar, paprika, onion powder, garlic powder, black pepper, salt, and cayenne pepper (if using).
Pour the mixture over the beef and vegetables in the slow cooker.
Add the Ranch seasoning mix and stir to combine.
Cover and cook on low for 6-8 hours or high for 3-4 hours.
Serve the sloppy joes on hamburger buns and enjoy!
Note: You can adjust the amount of Ranch seasoning mix and cayenne pepper to your taste preference. Additionally, you can add a can of drained and rinsed black beans or kidney beans for some extra protein and fiber.