Brown the ground beef with the diced onion in a large skillet over medium heat. Drain any excess grease.
Add the minced garlic and cook for 30 seconds until fragrant.
Transfer the beef mixture to the slow cooker.
Stir in the beef broth, tomato sauce, diced tomatoes, tomato paste, Worcestershire sauce, Italian seasoning, paprika, garlic powder, onion powder, and black pepper.
Cover and cook on LOW for 4 to 5 hours or HIGH for 2 to 3 hours.
About 30 minutes before serving, stir in the uncooked elbow macaroni.
Cover and continue cooking until the pasta is tender.
Stir in the shredded cheddar cheese and heavy cream until smooth and creamy.
Let the mixture rest for 5 minutes to thicken slightly.
Garnish with chopped parsley and serve warm.