Start by bringing a large pot of salted water to a boil over high heat. Add the medium pasta shells and cook until al dente, about 8-10 minutes. Once done, drain the pasta in a colander and set it aside.

In a large skillet over medium heat, add the ground beef, breaking it apart with a spatula as it cooks. Sauté until browned and fully cooked, about 6-8 minutes. Drain any excess grease from the skillet.

Add the diced onion and minced garlic to the skillet with the cooked beef. Sauté these aromatics over medium heat for about 3-4 minutes or until the onion is translucent and fragrant.

Pour in the creamy tomato sauce and sprinkle the Italian seasoning over the mixture in the skillet. Stir well to combine all the ingredients and let the mixture simmer gently for about 5 minutes.

Carefully fold the cooked pasta shells into the savory beef mixture in the skillet. Stir gently to coat all the shells evenly and continue cooking for an additional 2-3 minutes.

Remove the skillet from heat and stir in the shredded cheddar cheese until it melts seamlessly into the creamy sauce. If the sauce is too thick, add a splash of water or cream.

Serve the Creamy Beef and Shells warm in bowls, garnishing with fresh herbs if desired. Enjoy immediately.