Cook pasta according to package instructions. Reserve 1/2 cup of pasta water, then drain and set aside.
- Heat olive oil in a large skillet over medium heat. Add sliced chicken and season with salt, pepper, and optional Italian seasoning. Cook until golden and cooked through. Remove and set aside.
- In the same skillet, melt butter and sauté garlic for 30 seconds until fragrant.
- Add broccoli and cook for 2–3 minutes until slightly softened.
- Pour in heavy cream and bring to a gentle simmer.
- Stir in Parmesan and whisk until sauce is smooth. Add reserved pasta water if needed to thin the sauce.
- Add spinach and cook until wilted, about 1–2 minutes.
- Return chicken and cooked pasta to the skillet. Toss until everything is well coated in the sauce.
- Season with additional salt, pepper, and red pepper flakes to taste.
- Garnish with chopped parsley and extra Parmesan before serving.