In a large skillet or Dutch oven, brown the ground beef over medium-high heat, breaking it up with a spoon. Add the chopped onion and bell pepper and cook until softened, about 5-7 minutes.

Drain any excess grease from the skillet to prevent the sloppy joes from becoming too greasy.

Stir in the minced garlic and cook for another minute until fragrant, being careful not to burn it.

Reduce heat to medium and stir in the tomato sauce, tomato paste, brown sugar, apple cider vinegar, Worcestershire sauce, yellow mustard, and chili powder.

Bring the mixture to a gentle simmer, then reduce heat to low, cover, and cook for 10-15 minutes, stirring occasionally. Adjust seasoning with salt and pepper as needed, and add water or beef broth if the sauce is too thick.

While the sloppy joe mixture simmers, lightly toast the hamburger buns in a dry skillet, toaster, or under the broiler.

Spoon the hot sloppy joe mixture generously onto the toasted buns and serve immediately.