Pound chicken to even thickness.
Season both sides with salt and pepper.
Dredge chicken in flour completely.
Heat oil in large skillet.
Cook chicken 4 minutes per side.
Remove chicken and set aside.
Add mushrooms to same pan.
Sauté mushrooms until golden brown.
Add garlic and cook briefly.
Pour in Marsala wine carefully.
Add chicken broth to mixture.
Return chicken to the pan.
Simmer everything for 10 minutes.
Stir in butter for richness.
Garnish with fresh chopped parsley.