1. Bring a large pot of salted water to a boil, add linguine, and cook until al dente. Reserve 1 cup pasta water and drain.

2. Pat chicken dry and season both sides with salt and pepper.

3. Heat olive oil in a large skillet over medium high. Sear chicken 4 to 5 minutes per side until golden and cooked through. Transfer to a plate and rest.

4. Reduce heat to medium low. Add butter to the skillet. When melted, stir in garlic and cook 60 to 90 seconds until fragrant.

5. Pour in heavy cream and simmer gently 2 to 3 minutes, stirring.

6. Whisk in Parmesan and mozzarella until smooth and creamy. If too thick, stir in splashes of reserved pasta water to loosen.

7. Slice chicken into strips. Add linguine to the skillet and toss to coat. Nestle chicken on top and fold gently into the sauce.

8. Season to taste with additional salt, pepper, and red pepper flakes if using.

9. Remove from heat, sprinkle with parsley, and serve immediately.