1. Bring a large pot of salted water to a boil and cook penne until al dente, then drain and reserve 1/2 cup pasta water.

2. Pat chicken dry, coat all over with Cajun seasoning, and heat olive oil in a large skillet over medium-high heat.

3. Sear chicken 4 to 5 minutes per side until cooked through; transfer to a plate and rest 5 minutes, then slice.

4. Reduce skillet heat to medium, add butter, then sauté garlic for 30 to 60 seconds until fragrant.

5. Pour in heavy cream and simmer gently, stirring, until slightly thickened.

6. Stir in Parmesan until melted and smooth; season with salt and black pepper.

7. Add cooked penne to the sauce and toss to coat, loosening with splashes of reserved pasta water as needed.

8. Return sliced Cajun chicken to the skillet and toss gently to combine.

9. Finish with parsley and a squeeze of lemon juice if using; taste and adjust seasoning.

10. Serve hot with extra Parmesan on top.