01 - Pat chicken breasts dry with paper towels. Season both sides with salt and pepper. Dust chicken lightly with flour, shaking off excess.
02 - Heat olive oil in a large skillet over medium-high heat. Add chicken breasts and sear for 4 to 5 minutes per side until golden brown. Remove chicken from skillet and set aside.
03 - Reduce heat to medium. Add butter to the same skillet. Once melted, add mushrooms and onion. Sauté for 5 minutes until softened and golden. Add garlic and cook for 1 minute until fragrant.
04 - Pour in chicken broth, using a wooden spoon to scrape up browned bits from the bottom. Let simmer for 2 minutes until slightly reduced.
05 - Stir in heavy cream, Parmesan cheese, and thyme. Bring to a gentle simmer, stirring constantly until cheese melts.
06 - Return chicken to the skillet, nestling pieces into the sauce. Simmer uncovered for 7 to 10 minutes until chicken is cooked through and sauce has thickened.
07 - Transfer to serving plates. Garnish with additional fresh parsley. Serve immediately over pasta, rice, or mashed potatoes.