Start by bringing a large pot of salted water to a boil over high heat. Once boiling, add your choice of pasta and cook until al dente, typically 8-10 minutes. Reserve 1 cup of the pasta water for later use, drain the pasta and set it aside.

In a large skillet, melt 2 tablespoons of butter over medium heat. Add diced chicken breast, seasoning generously with salt and pepper. Cook for about 6-8 minutes until golden brown and cooked through. Remove from skillet and set aside.

In the same skillet, reduce heat and melt the remaining butter. Add minced garlic and diced onion, sautéing until the onion becomes translucent, about 3-4 minutes.

Pour in the heavy cream and chicken broth, stirring to combine. Season with Italian seasoning and sprinkle in red pepper flakes. Let simmer for about 5 minutes to thicken.

Return sautéed chicken and cooked pasta to the skillet with the sauce, tossing gently to coat. If too thick, add reserved pasta water until desired consistency. Cook together for an additional 2 minutes.

Finally, sprinkle with grated Parmesan cheese and garnish with freshly chopped parsley. Serve warm and enjoy!