Cook the Pasta:Bring a large pot of salted water to a boil. Add the pasta shells and cook until al dente, about 8–10 minutes. Drain and set aside.
Sauté the Aromatics:In a large skillet, heat olive oil over medium heat. Add the diced onion and cook for about 3 minutes until softened. Add ground beef and cook until browned and fully cooked, breaking it up as it cooks.
Add Seasoning and Garlic:Stir in the garlic and Italian seasoning. Cook for 1 minute until fragrant.
Build the Sauce:Stir in tomato paste, beef stock, and tomato sauce. Simmer uncovered for 6–8 minutes until slightly thickened.
Make it Creamy:Reduce heat to low. Stir in the heavy cream and shredded cheddar cheese. Mix until the cheese is fully melted and the sauce is smooth.
Combine Pasta and Sauce:Add the cooked pasta shells to the skillet. Stir to coat the pasta in the sauce. Let sit for 5–10 minutes to allow the flavors to meld.
Serve and Enjoy:Serve warm, topped with extra cheese or fresh parsley if desired.