
In a skillet over medium heat, add the oil. Add the onion and green pepper and cook until softened and lightly golden.
Add the garlic and stir to combine. Add the beef and cook until no longer pink.
Stir in the brown sugar, smoked paprika, salt, and pepper.
Stir in the tomato sauce, ketchup, Worcestershire sauce, and mustard.
Bring to a boil. Reduce the heat and simmer for 10 minutes until thickened, stirring occasionally.
Serve hot on warmed gluten-free buns and your favorite accompaniments.