01 - Bring a large pot of salted water to a boil. Cook the pasta according to package instructions until al dente. Drain and reserve ½ cup of the pasta water.
02 - Butterfly the chicken breasts. Season both sides with salt, pepper, and Italian herbs if desired.
03 - Heat olive oil in a large skillet over medium-high heat. Sear chicken breasts until golden brown and cooked through, approximately 5 to 6 minutes per side. Transfer to a plate, cover loosely, and allow to rest.
04 - In the same skillet, reduce heat to medium and add the butter. Sauté the onion for 2 to 3 minutes until softened. Add minced garlic and cook for 1 minute until aromatic.
05 - Deglaze the skillet with chicken broth, scraping any browned bits from the pan. Pour in the heavy cream and allow to simmer gently. Stir in the Parmesan cheese until the sauce becomes smooth and creamy. Adjust seasoning with additional salt and pepper if needed.
06 - Slice the rested chicken breasts thinly. Return chicken to the pan along with cooked pasta. Toss thoroughly, adding reserved pasta water as needed until desired sauce consistency is achieved.
07 - Stir in chopped parsley and serve immediately, garnished with extra parsley and Parmesan cheese.