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

In a large skillet, heat a drizzle of olive oil over medium heat. Add the chopped onion and minced garlic. Sauté for about 2-3 minutes until the onion is translucent and fragrant.

Add the ground beef to the skillet and cook for about 5-7 minutes, breaking it apart, until browned and fully cooked with no pink remaining.

Pour in the creamy tomato sauce and add the Italian seasoning. Stir well and allow to simmer gently on low for about 3 minutes, adjusting seasoning with salt and pepper.

Fold in the cooked pasta shells, mixing gently to coat in the creamy sauce. Heat for an additional 2-3 minutes until warmed through.

Remove from heat and garnish with freshly chopped herbs or cheese if desired. Serve immediately hot.