1. Prepare the chicken: Start by patting the chicken pieces dry with paper towels. This helps them brown better. Season the chicken all over with half of the salt and pepper.

2. Sear the chicken: Heat the olive oil in a large skillet or Dutch oven over medium-high heat. Once shimmering, add the chicken pieces in a single layer, making sure not to overcrowd the pan. Cook for 3-4 minutes per side, until golden brown and cooked through. Remove the chicken from the skillet and set aside on a plate.

3. Saute aromatics: Reduce the heat to medium. Add the chopped onion to the same skillet and cook for 3-4 minutes until softened and translucent. Stir in the minced garlic and Italian seasoning, cooking for another minute until fragrant. Be careful not to burn the garlic.

4. Create the creamy sauce: Pour in the chicken broth, scraping up any browned bits from the bottom of the pan with a wooden spoon. Bring to a simmer. Reduce the heat to low, then whisk in the heavy cream and softened cream cheese until the cream cheese is fully melted and the sauce is smooth. Season with the remaining salt and pepper.

5. Add spinach and chicken: Stir in the fresh spinach, allowing it to wilt into the sauce for 2-3 minutes. Once the spinach has softened, return the cooked chicken pieces to the skillet, tossing gently to coat them in the creamy sauce.

6. Finish and serve: Sprinkle the Parmesan cheese over the chicken and sauce. Let it simmer for another 1-2 minutes, allowing the cheese to melt and the sauce to thicken slightly. Garnish with fresh chopped parsley, if desired, and serve immediately.