Cook the pasta in a large pot of salted boiling water for 8-10 minutes until al dente. Reserve 1 cup of pasta water, drain, and set aside.

In a large skillet, melt 2 tablespoons of butter over medium heat. Add chicken breast pieces, seasoned with salt and pepper, and sauté for 6-8 minutes until golden brown. Transfer to a plate and keep warm.

In the same skillet, melt another tablespoon of butter. Add finely chopped garlic and onion, sauté for 3-4 minutes until translucent.

Stir in heavy cream and chicken broth along with Italian seasoning and red pepper flakes. Simmer for about 5 minutes until the sauce thickens.

Combine the sautéed chicken and cooked pasta with the sauce, tossing gently over medium heat for 2 minutes to coat.

Serve hot, topped with freshly grated Parmesan cheese and chopped parsley.