Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente. Drain the pasta and set it aside.
In a frying pan, heat the olive oil over medium-high heat. Add the chicken pieces, seasoning them with salt, pepper, and red pepper flakes (if using). Cook for about 5-7 minutes or until the chicken is cooked through and no longer pink inside. Remove the chicken from the pan and set aside.
In the same frying pan, add the minced garlic and sauté for about 1 minute until fragrant, being careful not to burn it.
Pour in the chicken broth and bring to a simmer, scraping any browned bits from the bottom of the pan. Allow it to cook for about 3-5 minutes.
Lower the heat and stir in the heavy cream. Cook for another 2-3 minutes, allowing it to thicken slightly.
Gradually whisk in the grated Parmesan cheese until fully melted and incorporated into the sauce.
Return the cooked chicken to the pan, and add the drained pasta. Toss everything together until the pasta is well coated in the creamy sauce.
Serve immediately, garnished with fresh parsley.