Brown the ground beef in a large deep skillet over medium-high heat, breaking it apart until it’s no longer pink. Drain any excess fat so the sauce stays rich but not greasy, then keep the skillet hot.

Add the diced onion and cook for 3 minutes until softened. Stir in the minced garlic and cook 1 more minute until fragrant.

Add the uncooked shells, beef broth, diced tomatoes, Rotel, Italian seasoning, smoked paprika, salt, and black pepper, then stir to combine and evenly coat the pasta. Bring the mixture to a boil.

Reduce heat to medium-low, cover the skillet, and cook for 12–15 minutes until the pasta is tender and most liquid is absorbed, shaking the pan once if needed. Watch for bubbling through the cover as the sauce thickens around the shells.

Stir in the heavy cream and simmer uncovered for 2–3 minutes until the sauce thickens and looks creamy. Keep the heat at a gentle simmer to avoid scorching.

Remove from heat, then stir in the shredded cheddar until fully melted and glossy. Serve immediately while the cheese pools inside the shells.