Bring a large pot of salted water to a rolling boil. Add the pasta shells and cook according to package instructions until al dente, about 8-10 minutes. Drain and set aside.

In a large skillet, heat oil over medium heat. Add ground beef, breaking it up, and sauté for 5-7 minutes until browned. Add diced onions and minced garlic, cooking for another 2-3 minutes until onions are translucent.

Pour in the beef broth and sprinkle Italian seasoning, stirring to combine. Simmer for 5 minutes to meld flavors.

Reduce heat to low and stir in heavy cream, simmering for another 5 minutes until the sauce thickens.

Fold in cooked pasta shells, ensuring they are well-coated in the creamy beef mixture. Mix for about 2 minutes.

Scoop portions onto warm plates, garnishing with extra Italian seasoning if desired. Serve fresh.