Authentic Marsala is finished with a small amount of the wine and does not necessarily have mushrooms.
3½ pounds skinless, boneless chicken breasts
½ cup cold unsalted butter
2 cups fresh mushrooms
½ bulb garlic
½ cup all-purpose flour
¼ cup olive oil
1 cup Marsala wine
Rinse the chicken and pat dry with paper towels. Place the breasts between layers of plastic wrap, and pound until thin. Beat the eggs in a bowl. Cut the butter into small pats. Clean and slice the mushrooms. Peel and mince the garlic.
Dust the chicken with the flour. Dip in the eggs, and return to the flour. Shake off excess flour.
Heat the oil to medium-high temperature in a large sauté pan. Add the chicken, and brown on one side. Turn over, and add the mushrooms and garlic.
Pour in the wine, and reduce to half the volume.
Add the pats of cold butter, and stir into the sauce. Serve the chicken with the sauce.