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

2. Pat chicken dry, toss with Cajun seasoning, salt, and pepper until evenly coated.

3. Heat olive oil in a large skillet over medium-high heat; sear chicken 3 to 4 minutes per side until cooked through. Transfer to a plate and slice.

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

5. Pour in heavy cream; simmer gently 2 to 3 minutes while stirring so it does not scorch.

6. Whisk in shredded mozzarella a handful at a time until smooth and creamy.

7. Taste and season the sauce with additional Cajun seasoning, salt, and pepper as desired.

8. Add drained penne to the skillet; toss to coat, loosening with splashes of reserved pasta water as needed.

9. Return sliced chicken to the pan; stir until everything is hot and glossy.

10. Finish with lemon juice and chopped parsley; serve immediately.