Fill a large pot with salted water and bring to a rolling boil. Cook shell pasta according to package directions until al dente. Drain and set aside, reserving 1/2 cup pasta water.

Heat olive oil in a large skillet over medium-high heat. Add ground beef and cook 6-8 minutes, breaking up with wooden spoon until browned. Drain excess fat if needed.

Add butter to the same pan. Once melted, add diced onion and cook 4-5 minutes until softened. Add garlic and cook 1 minute until fragrant.

Stir in Italian seasoning, paprika, oregano, garlic powder, onion powder, salt, pepper, and red pepper flakes. Cook 30 seconds until aromatic.

Pour in beef broth and drained tomatoes. Bring to a gentle simmer and cook 3-4 minutes to meld flavors.

Reduce heat to medium-low and slowly add heavy cream, stirring constantly. Simmer gently 5-6 minutes until sauce begins to thicken.

Remove from heat and gradually add cheddar and mozzarella cheeses, stirring until melted and smooth. Add pasta water if sauce is too thick.

Add cooked pasta to the creamy beef mixture, folding gently until well coated. Let stand 2-3 minutes to absorb flavors.

Taste and adjust seasonings. Garnish with fresh parsley and serve immediately while hot and creamy.