Begin by bringing a large pot of salted water to a rolling boil over high heat. Add your choice of pasta and cook according to package instructions until al dente, typically taking about 8-10 minutes. Reserve 1 cup of pasta water, then drain the rest in a colander.

In a large skillet, melt 2 tablespoons of butter over medium heat. Add bite-sized pieces of chicken breast, seasoning them with salt and pepper. Cook for 6-8 minutes until golden and cooked through, then remove and set aside.

In the same skillet, add another tablespoon of butter and reduce heat to medium-low. Sauté minced garlic and chopped onion for 3-4 minutes until fragrant and translucent. Stir in heavy cream and chicken broth, then add Italian seasoning and red pepper flakes. Let simmer for about 5 minutes to thicken slightly.

Return the cooked chicken to the skillet along with the drained pasta. Toss everything together until the pasta is nicely coated with the creamy sauce. If too thick, gradually mix in reserved pasta water to reach desired consistency. Adjust seasoning, and cook for another 2 minutes.

Remove from heat and serve warm, topped with grated Parmesan cheese and freshly chopped parsley.