Heat olive oil in a large pot over medium heat. Add onion and sauté until translucent.
Add ground beef and cook until browned. Stir in garlic, Italian seasoning, red pepper flakes, salt, and black pepper.
Mix in tomato paste and cook for 2 minutes.
Add crushed tomatoes, beef broth, milk, and pasta. Stir well and bring to a boil.
Reduce heat, cover, and simmer for about 12 minutes, stirring occasionally, until pasta is tender.
Stir in heavy cream and shredded cheddar. Simmer uncovered for 2–3 minutes until creamy.
Garnish with chopped parsley before serving.