01 - Season both sides of each chicken breast evenly with salt and black pepper, pressing gently to help the seasoning adhere.
02 - Heat olive oil in a large skillet over medium-high heat. Place chicken breasts in the pan and cook for 5 to 6 minutes per side until golden brown and cooked through. Transfer to a plate and tent with foil to keep warm.
03 - Reduce heat to medium and add butter to the same skillet. Once melted, add sliced mushrooms and sauté for 4 to 5 minutes until browned and tender.
04 - Add minced garlic and thyme to the skillet. Cook for 1 minute until fragrant, stirring constantly to prevent burning.
05 - Pour in chicken stock, using a wooden spoon to scrape up any browned bits from the bottom of the pan. Simmer for 2 minutes until slightly reduced.
06 - Stir in heavy cream and Parmesan cheese. Simmer for 2 to 3 minutes, stirring occasionally, until sauce thickens and cheese melts completely.
07 - Return chicken breasts to the skillet, nestling them into the sauce. Simmer for 2 to 3 more minutes until chicken is heated through.
08 - Sprinkle chopped fresh parsley over the dish and serve immediately while hot.