Heat a large deep skillet or Dutch oven over medium-high heat. Add the lean ground beef and diced onion, breaking the beef into small pieces, and cook for about 5–7 minutes until the meat is browned and the onion has softened; drain excess fat if necessary.

Add the minced garlic, tomato paste, paprika, Italian seasoning, salt, and black pepper. Stir and cook for 30–60 seconds, just until the garlic is fragrant and the tomato paste is mixed through the beef.

Sprinkle the all-purpose flour over the beef mixture and stir well. Cook for 1 minute so the flour coats the meat and can help thicken the sauce.

Pour in the tomato sauce and beef broth, stirring thoroughly to combine. Scrape up any browned bits from the bottom of the skillet because they add extra savory flavor to the sauce.

Stir the uncooked elbow macaroni into the skillet. Bring the mixture to a gentle boil, then reduce the heat to medium-low before covering the pan.

Cover and simmer for about 10–15 minutes, stirring every few minutes so the pasta does not stick as the sauce thickens. Continue cooking until the macaroni is tender, adding a small splash of broth or water if the liquid is absorbed before the pasta is fully cooked.

Remove the skillet from the heat and stir in the shredded sharp cheddar until melted and creamy. Taste the finished dish and adjust the salt and pepper before serving immediately.