In a large skillet over medium heat, heat oil. Add onions and sauté until translucent, about 2 minutes. Add red peppers and sauté for a couple minutes.
Add ground beef, breaking it into small pieces, and generously season with ground sea salt and freshly ground black pepper. Cook until almost done before adding garlic; sauté for 1 to 1 ½ minutes.
Add ketchup, tomato paste, mustard, brown sugar, Worcestershire sauce, hot sauce, and beef broth. Stir the ingredients very well and cook until all the liquid and fat is gone, stirring often, 25 to 30 minutes.
Start cooking the macaroni.
While the pasta and meat mixture is cooking, start the cheese sauce. In a saucepan over medium heat, add butter and when melted and it starts sizzling, add flour; cook for 2 minutes, stirring constantly.
Add ½ cup of milk at a time, stir until smooth before adding another cup.
Add Dijon mustard, smoked paprika, garlic powder and cayenne pepper; whisk until blended.
Adding a handful of shredded cheese at a time, whisk until incorporated before adding more; whisking well after each addition.
When time is up, add cooked macaroni to the meat mixture, stirring until evenly mixed and pasta is nicely coated.
Pour the cheese sauce over and stir once again. When serving, sprinkle on some fresh chopped parsley.