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, slightly less than the package instructions for a perfect bite. Drain the pasta in a colander and set aside, allowing the hot steam to escape.

In a large skillet, heat 2 tablespoons of cooking oil over medium heat. Once hot, add the chopped onion and minced garlic, sautéing for 3-4 minutes until the onion is translucent and fragrant.

Add the ground beef to the pan, breaking it apart with a spatula. Cook for about 6-8 minutes, stirring occasionally, until the meat is well-browned and no longer pink. If there's excess fat, drain it off.

Pour in the creamy tomato sauce, along with the Italian seasoning, salt, and pepper. Stir the mixture gently to combine all ingredients thoroughly, allowing the sauce to heat through for about 2-3 minutes.

Fold the cooked pasta shells into the skillet, carefully incorporating them into the creamy beef mixture. Stir for another 2-3 minutes until every shell is perfectly coated with the sauce.

Once heated through, remove the skillet from heat. Garnish with freshly chopped parsley or a sprinkle of grated cheese before serving.