01 - Season both sides of each chicken breast with salt, pepper, and Italian seasoning, pressing gently to help the spices adhere.
02 - Heat olive oil and butter in a large skillet over medium-high heat. Add chicken breasts and cook for 5-7 minutes per side until golden brown and cooked through. Transfer chicken to a plate and set aside.
03 - Reduce heat to medium. Add onion and garlic to the same skillet; sauté for 2-3 minutes until fragrant and translucent, taking care not to burn the garlic.
04 - Pour in chicken broth, using a wooden spoon to scrape up any browned bits from the bottom of the pan. Let simmer for 2 minutes to reduce slightly.
05 - Stir in heavy cream and Parmesan cheese, whisking continuously until cheese melts and sauce becomes smooth. Simmer gently for 2-3 minutes until sauce thickens enough to coat the back of a spoon.
06 - Return chicken breasts to the skillet, spooning sauce over the top. Simmer for 3-5 minutes until chicken is heated through and flavors meld together.
07 - Sprinkle with fresh parsley and additional Parmesan cheese if desired. Serve immediately alongside mashed potatoes, pasta, or steamed vegetables.