Season the chicken pieces with salt and pepper. In a large pot or Dutch oven, heat the olive oil and one tablespoon of butter over medium-high heat. Add the chicken and cook until it's golden brown and cooked through, about 5-7 minutes. Remove the chicken from the pot and set it aside.

Add the remaining tablespoon of butter to the pot. Add the chopped onion and cook until softened, about 3 minutes. Add the minced garlic and cook for another minute until fragrant, being careful not to let it burn.

Pour in the chicken broth, scraping up any browned bits from the bottom of the pot. Stir in the heavy cream and Italian seasoning. Bring the mixture to a simmer.

Add the uncooked penne pasta to the pot. Stir well, ensuring the pasta is submerged in the liquid. Let it return to a simmer, then reduce the heat to medium-low, cover, and cook for 12-15 minutes, or until the pasta is al dente. Stir occasionally to prevent sticking.

Once the pasta is cooked, turn off the heat. Stir in the grated Parmesan cheese until it has completely melted into the sauce. Return the cooked chicken to the pot and stir to combine.

Garnish with freshly chopped parsley. Serve immediately and enjoy!