To the chicken cutlets, lightly salt and pepper each side. Dredge the seasoned chicken in the 1/2 cup of flour.
Heat a large skillet over medium-high heat, and add the olive oil. Place the floured chicken cutlets into the skillet and saute on each side for approximately 3 minutes. Remove the chicken from the skillet and set aside.
To the same skillet, add the shallots and saute for approximately 3 minutes or until slightly translucent. Add the mushrooms and saute for 3 more minutes. Add the garlic, and saute for 1 more minute. Remove from the skillet and set aside in a bowl.
To the hot skillet add the butter and let melt. Add the flour and mix until a paste forms, and saute for about 1 minute stirring constantly. Add the Marsala wine, and bring to a simmer.
As soon as the sauce thickens, add the chicken broth, and stir until slightly thick. Add back the mushroom mixture and chicken to the sauce. Coat the chicken with the sauce, and remove from heat. Serve right away.
Standard boneless, skinless chicken breasts can also be used. It is recommended that the chicken breasts be sliced in half horizontally to create a thinner cutlet.