In small saucepot, cook wine and shallots over high heat 8 to 10 minutes or until wine is reduced by half. Reserve 2 tablespoons flour. In pie plate or wide, shallow bowl, combine salt, pepper and remaining flour. Dip chicken in flour mixture to coat.
In large nonstick skillet, melt 2 tablespoons butter over medium-high heat. Add chicken and cook 8 to 10 minutes or until chicken is golden brown and almost cooked through, turning once. Transfer chicken to plate.
In same skillet, cook mushrooms and remaining 4 tablespoons butter over medium heat 4 to 5 minutes or until mushrooms are tender. Reduce heat to low. Stir in reserved flour and cook 1 minute, stirring occasionally.
Add cream, broth and wine mixture, and heat to boiling over medium heat. Reduce heat to medium-low and simmer 4 minutes. Return chicken to skillet and cook 1 to 2 minutes or until chicken loses its pink color throughout and internal temperature reaches 16
Serve chicken topped with Marsala sauce. Sprinkle with parsley, if desired.