1. Prepare the Chicken: Start by patting your cubed chicken breasts dry with paper towels. This helps them brown better. Season the chicken generously with salt and pepper. Heat the olive oil in a large skillet over medium-high heat. Once the oil is shimmering, add the chicken 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 it aside on a plate. It doesn’t need to be perfectly cooked through at this stage, as it will finish cooking in the sauce.

2. Saute the Aromatics: Reduce the heat to medium. Add the chopped onion to the same skillet, scraping up any browned bits from the bottom of the pan. Cook the onion for 3-5 minutes, until it softens and becomes translucent. This step builds a foundational layer of flavor.

3. Add Garlic and Seasoning: Stir in the minced garlic and Italian seasoning. Cook for another minute, until the garlic becomes fragrant. Be careful not to burn the garlic, as this can make it bitter.

4. Deglaze with Broth: Pour in the chicken broth, scraping the bottom of the skillet again with a wooden spoon to release any remaining flavorful browned bits. Bring the broth to a simmer and let it cook for 2-3 minutes, allowing it to reduce slightly and concentrate its flavors.

5. Create the Creamy Sauce: Reduce the heat to low. Stir in the heavy cream and grated Parmesan cheese. Whisk gently until the cheese is fully melted and the sauce is smooth and slightly thickened. The sauce should be creamy and coat the back of a spoon.

6. Combine and Serve: Return the cooked chicken to the skillet, tossing it gently to coat it completely in the creamy sauce. Let it simmer for 2-3 minutes, allowing the chicken to warm through and absorb the flavors of the sauce. Taste and adjust seasoning if necessary. Garnish with fresh chopped parsley, if using, and serve immediately.