Preheat oven to 350oF. Simmer Munchin' Mix in broth for 5 minutes. Set aside. Wash and dry the mushrooms. Remove stems and set aside caps. Finely chop stems. Simmer stems and onion in a frying pan, in butter or oil for 2 to 3 minutes, until onion is translucent. Remove from heat, add Munchin' Mix in broth, bread crumbs, salt and pepper and mix thoroughly.
Stuff mushrooms and sprinkle with cheese. Place mushrooms in baking pan. Pour ½ cup of broth (or water) into baking pan to help steam the mushrooms. Bake at 350oF. for 45 minutes until mushrooms are tender and dark and cheese is browned. Serve hot or room temperature.
Recipe makes 10 large stuffed mushrooms.