01 - Season both sides of each chicken breast generously with salt, pepper, and Italian seasoning, pressing the spices into the meat to ensure even coating.
02 - Heat olive oil and butter in a large skillet over medium-high heat until butter foams. Add chicken breasts and cook for 5 to 7 minutes per side until golden brown and internal temperature reaches 165°F. Transfer to a plate and cover loosely with foil.
03 - Reduce heat to medium. Add onion and garlic to the same skillet, sautéing for 2 to 3 minutes until fragrant and translucent, being careful not to burn the garlic.
04 - Pour chicken broth into skillet, using a wooden spoon to scrape up browned bits from the bottom. Allow mixture to simmer for 2 minutes, reducing slightly.
05 - Stir in heavy cream and Parmesan cheese, whisking continuously until cheese melts and sauce becomes smooth and velvety. Simmer gently for 2 to 3 minutes until sauce thickens enough to coat the back of a spoon.
06 - Return chicken to skillet, spooning sauce over each piece. Simmer for 3 to 5 minutes until chicken is heated through and flavors meld. Sprinkle with fresh parsley and additional Parmesan if desired. Serve immediately.