1. Season the chicken: Pat chicken dry. Toss with 1 tsp Cajun seasoning, 1/2 tsp salt, and black pepper.

2. Sear the chicken: Heat olive oil in a large skillet over medium-high. Add chicken in a single layer; cook 4–6 minutes, turning once, until browned and cooked through. Reduce heat to medium; add 4 tbsp butter and half the minced garlic. Toss to coat 30–60 seconds. Transfer chicken to a warm plate.

3. Boil the pasta: Cook rotini in salted boiling water until al dente. Reserve 1/2 cup pasta water; drain.

4. Build the Cajun Alfredo: In a saucepan (or the wiped skillet), melt 2 tbsp butter over medium heat. Add remaining garlic; sauté 30 seconds. Stir in heavy cream, remaining 1 tsp Cajun seasoning, remaining 1/2 tsp salt, and red pepper flakes. Simmer 2–3 minutes until lightly thickened.

5. Finish the sauce: Whisk in Parmesan until smooth. Loosen with splashes of reserved pasta water until glossy and clings to a spoon. Optional: stir in lemon juice.

6. Sauce the pasta: Add drained pasta to the sauce; toss until every twist is coated and silky.

7. Plate and garnish: Serve pasta with garlic-butter chicken bites on the side (or fold chicken into the pasta). Sprinkle with parsley and more Parmesan if you like. Enjoy hot.