In a medium bowl, whisk together the ketchup, tomato paste, water, Worcestershire sauce, brown sugar, salt and pepper. Set aside.
Heat a 12” electric skillet to 300 °F. Brown the ground beef in the skillet, breaking it apart into crumbles as it cooks (about 5 minutes)
Add the garlic, onions and bell peppers to the electric skillet and cook for 2 more minutes. Add the ketchup mixture. Mix well.
Reduce heat to 250 °F and simmer for about 10 minutes, stirring occasionally, until the mixture has thickened slightly.
Toast the buns. Serve the sloppy Joe mixture over the toasted buns.
Notes
If you like the bitter contrast with the sweet tang of the tomato sauce, use the green pepper. If you prefer a sweeter pepper, I recommend the red pepper (it will also match the red tomato sauce, blending it in for those picky eaters).
Store leftovers in a covered container in the fridge for up to 3 to 4 days.
Reheat the meat mixture in the electric skillet on medium heat or on the stove.