I got this recipe here at TKL and I can vouch for how great it is!

Chicken Breasts Lombardy

8 boneless chicken breast halves
1/2 cup all-purpose flour
1 cup butter or margarine, divided
salt and pepper
1-1/2 cups (or more) sliced fresh mushrooms
3/4 cup Marsala wine
1/2 cup chicken broth
1/2 cup shredded Fontina or mozzarella cheese (I use a little more)
1/2 cup freshly grated Parmesan cheese

Cut each piece of chicken in half so you have breast quarters. Place each piece between 2 sheets of saran wrap or waxed paper and flatten to 1/2” thickness using a meat mallet.
Dredge chicken lightly with flour. Place 4 pieces at a time to 2 TBSP melted butter in a large skillet; cook over low heat 3 to 4 minutes on each side or until chicken is golden brown. Place chicken in a greased 13 x 9 x 2"”baking dish, overlapping edges; sprinkle with salt and pepper to taste. Repeat procedure with remaining chicken, adding 2 TBSP butter to skillet each time, or as needed. Reserve drippings in skillet.
Saute mushrooms in butter. Sprinkle evenly over chicken.
Stir wine and chicken broth into pan drippings in skillet. Simmer 10 minutes, stirring occasionally. Season with salt and pepper if desired. Spoon sauce evenly over chicken.
Bake at 425 degrees for 12 minutes. Combine cheeses and sprinkle over chicken. Bake an additional 5 minutes.
Carolyn-NJ I searched the recipe name and came up empty but can hardly believe it's never been posted - maybe under another name. Notes in "my" cookbook say that this Southern Living recipe originally appeared in their November, 1978 issue. It's been a favorite in our house for years. Altho the directions read like everything is done at once, I almost always prepare it ahead and reheat, adjusing time/temp. It also freezes successfully.