Bring salted water to a boil and cook pasta until al dente. Reserve ½ cup pasta water, then drain.
Melt butter in a pan over medium heat. Add garlic and sauté briefly until fragrant.
Pour in heavy cream and let it gently simmer until slightly thickened.
Stir in Parmesan, Italian seasoning, salt, and pepper. Mix until smooth and creamy.
Add cooked pasta and a splash of reserved water. Toss until evenly coated.
Top with parsley, extra Parmesan, and optional chili flakes. Let sit for 1–2 minutes before serving.