Season the chicken breasts with salt and pepper, then dredge in flour.
Heat olive oil in a skillet over medium heat and cook the chicken for about 5 minutes on each side.
Remove the chicken and set aside.
In the same skillet, add butter and sliced mushrooms, sautéing until tender.
Pour in the Marsala wine, scraping up browned bits, and add chicken broth.
Return the chicken to the skillet and simmer for an additional 5 minutes.
Allow the sauce to thicken, then serve garnished with fresh parsley.