Cook the pasta: Boil the pasta in salted water until al dente, reserving about ½ cup of pasta water before draining.
Season the chicken: Cut the chicken into even pieces and season with salt and black pepper.
Brown the chicken: Cook the chicken in olive oil over medium-high heat for 5 to 6 minutes until golden and cooked through, then set aside.
Melt the butter: Lower the heat and melt butter in the same skillet, loosening the browned bits left by the chicken.
Cook the garlic: Add minced garlic and cook for 30 to 45 seconds until fragrant without browning it.
Add cream: Pour in the heavy cream and simmer gently for 2 to 3 minutes.
Add Parmesan: Stir in Italian seasoning and Parmesan over low heat until the sauce is smooth.
Adjust the sauce: Add reserved pasta water a little at a time until the sauce is creamy and coats a spoon.
Combine: Toss the pasta through the sauce, return the chicken, and warm everything together for about 1 minute.
Finish and serve: Taste for seasoning, add parsley or red pepper flakes if desired, and serve hot.