In a large pot, heat the olive oil over medium heat. Add the ground beef, onion, salt, and pepper. Cook until the onions are soft and the beef is cooked through. Add the garlic powder, paprika, chili powder, and cayenne pepper. Cook for an additional minute. Add the pasta, milk, beef broth, ketchup and mustard. Stir to combine and bring to a simmer. Simmer for about 10-15 minutes or until the pasta is al dente. Stir the pasta frequently! Add more liquid (milk or broth) as needed. Turn the heat to low. Stir in the cauliflower, relish, and cheese and cook for an additional 5 minutes until melty and smooth.