01 - Prepare pasta according to package directions until al dente. Drain, reserving 1/2 cup pasta water, and set aside.
02 - Season chicken breasts evenly with salt and black pepper on both sides.
03 - Heat olive oil in a large skillet over medium-high heat. Sear chicken for 5 to 7 minutes per side until golden and cooked through. Remove from skillet, rest for 3 minutes, then thinly slice.
04 - Reduce skillet heat to medium. Add butter and garlic; sauté for one minute until fragrant.
05 - Pour in heavy cream and chicken broth, stirring until combined. Bring to a gentle simmer.
06 - Mix in grated Parmesan, Italian seasoning, and crushed red pepper flakes if using. Simmer 2 to 3 minutes until sauce thickens slightly.
07 - Add cooked pasta to skillet, tossing to coat in sauce. Adjust thickness as needed by adding reserved pasta water incrementally.
08 - Return sliced chicken to skillet. Gently toss to blend and warm through.
09 - Adjust seasoning with salt and pepper as preferred.
10 - Serve immediately garnished with chopped fresh parsley and additional grated Parmesan.