Heat the oil over medium-high heat in a large skillet
Add the beef and cook, breaking up with a wooden spoon, until starting to brown (about 10 minutes)
If there's a lot of grease, drain the beef (optional)
Add the onions and cook for 5 minutes or until starting to turn translucent
Add the roasted red pepper, Worcestershire sauce, tomato paste, onion powder, and garlic powder. Stir to combine and cook for a couple minutes
Add the brown sugar, stir to combine, then add the marinara sauce
Turn the heat down to medium or medium-low and let simmer for about 15 minutes, stirring occasionally
Toast the buns (and melt your chosen cheese on the buns) as you like, and serve!