Heat 3 tbsp butter in a skillet on medium-high heat.
Dredge 2 lbs chicken breasts in 1/2 cup flour.
Cook each side of the chicken breasts for 3 minutes.
While cooking chicken and mushrooms: mix 1 can Campbell's cream of mushroom soup, 1/2 cup chicken broth, 1 cup sour cream and 1 packet of onion soup mix together.
Preheat oven to 350
When chicken is finished, place in a glass casserole dish.
Add 1 tbsp butter to the skillet.
Saute mushrooms for 3 minutes.
Place mushrooms over the chicken in the casserole dish.
Spread mushroom soup mix over the chicken and mushrooms.
Top chicken with Muenster cheese.
Cover casserole dish with aluminum foil.
Bake for 30 minutes covered.
Remove foil.
Bake for 5 minutes.
