1. Pat the chicken dry and season with salt and pepper.

2. Heat the olive oil and 1 tablespoon butter in a large skillet over medium-high heat. Sear chicken 5 to 6 minutes per side until golden and cooked through; transfer to a plate and tent with foil.

3. Reduce heat to medium. Add remaining 3 tablespoons butter to the skillet. Stir in garlic and cook 30 seconds until fragrant.

4. Pour in chicken broth and scrape up any browned bits. Stir in heavy cream and bring to a gentle simmer.

5. Whisk in Parmesan until smooth. Keep the sauce at a low simmer, stirring, 2 to 3 minutes to slightly thicken.

6. Meanwhile, cook linguine in salted boiling water until al dente. Reserve 1/2 cup pasta water, then drain.

7. Slice the chicken. Add linguine to the skillet and toss in the sauce, loosening with splashes of pasta water as needed until glossy and silky.

8. Fold in the sliced chicken, parsley, and red pepper flakes. Add lemon juice if using. Taste and adjust salt and pepper.

9. Serve hot with extra Parmesan and parsley.