01 - Season chicken breasts evenly with salt and pepper. Dredge lightly in flour, shaking off excess coating.
02 - Heat olive oil in large skillet over medium-high heat. Sear chicken 4-5 minutes per side until golden brown and cooked through. Remove to plate, cover with foil.
03 - Add mushrooms and onion to same skillet. Sauté 4 minutes until softened. Add garlic, cook 1 minute until fragrant.
04 - Pour in chicken broth, scraping browned bits from pan bottom. Stir in heavy cream, Dijon mustard, thyme, and rosemary. Bring to gentle simmer.
05 - Return chicken to skillet, nestling into sauce. Simmer 5-7 minutes until sauce thickens and chicken is heated through.
06 - Stir in fresh parsley. Taste and adjust seasoning if needed. Serve chicken with sauce, garnished with additional parsley.