Chicken Marsala

From grocery.coop

4 chicken breasts, boneless and skinless
2 tablespoons unbleached flour
1/2 teaspoon salt
1/2 teaspoon freshly ground black pepper
2 tablespoons olive oil
1 large onion, sliced thin
8 oz. cremini mushrooms, sliced thin
2 cloves garlic, chopped
1/2 cup Marsala wine
1 cup chicken broth
2 tablespoons chopped parsley

1. Mix the flour, salt and pepper in a pie pan. Dredge the chicken in the flour mixture to coat, saving any leftover flour mixture. 
2. In a large heavy skillet heat the olive oil over medium high heat and brown chicken in 2 batches, transferring with tongs to a platter when browned.
3. To the skillet, add onion and mushrooms, stirring occasionally, until the mushrooms are lightly browned. Add garlic and stir for 1 minute. Sprinkle any remaining flour mixture over the mushrooms and stir. Add Marsala and cook, stirring until almost evaporated. Add broth and chicken with any juices that have accumulated on plate and simmer, turning chicken once, until cooked through, about 15 minutes. Transfer chicken to the platter and keep warm.
4. Simmer mushroom sauce until liquid is reduced and thickened. Remove skillet from heat and stir in remaining 2 tablespoons butter and salt and pepper to taste. Spoon mushroom sauce around chicken and sprinkle with parsley.