Chicken Breasts Lombardy

Melt 2 tablespoons butter in a large, nonstick skillet over medium-high heat. Add mushrooms and cook, stirring constantly, just until tender, 3 to 5 minutes. Remove from the heat and set aside.

Cut each chicken breast in half lengthwise. Place between two sheets of heavy-duty plastic wrap and flatten with a meat mallet or rolling pin to a thickness of 1/8 inch. Dredge chicken pieces in flour.

Preheat the oven to 450 degrees F (230 degrees C). Lightly grease a 9x13-inch baking dish.

Melt 1 to 2 tablespoons butter in the same skillet over medium heat. Add chicken in batches, adding more butter as needed, and cook until golden, 3 to 4 minutes per side. Transfer chicken to the prepared baking dish, overlapping to fit if necessary. Reserve pan drippings in the skillet. Sprinkle mushrooms evenly over chicken.

Add wine and broth to the skillet; bring to a boil. Reduce the heat and simmer, uncovered and stirring occasionally, for 10 minutes. Stir in salt and pepper. Pour sauce over chicken. Combine mozzarella and Parmesan with green onions; sprinkle over chicken.

Bake, uncovered, in the preheated oven until cheese is melted and chicken is no longer pink in the center and the juices run clear, 12 to 14 minutes.