Brown the beef/turkey. Heat a large skillet or deep pan over medium-high heat. Add the minced beef and diced onion, breaking up the meat with a wooden spoon until browned and cooked through (about 6–8 minutes). Drain off any excess fat if needed (not required if using turkey)
Add seasonings: Stir in the tomato purée, garlic powder, onion powder, paprika, mustard, salt, and pepper. Cook for 1 minute until fragrant.
Simmer the pasta: Pour in the beef stock and milk, then tip in the raw macaroni. Bring to a boil, then turn the heat down to medium-low, cover with a lid, and let it simmer for 10 to 12 minutes. Stir occasionally so the pasta doesn't stick to the bottom.
Melt the cheese: Once the pasta is tender and has absorbed most of the liquid, remove from the heat. Stir in the grated cheddar until fully melted and glossy.
Rest and serve: Let it stand uncovered for 3 minutes—the sauce will thicken up as it cools slightly.
