|Heat oven to 375 degrees.|
Melt butter in skillet. Break one slice of bread into blender. Add one quarter of onion and 1/2 cup mushroom stems. Grate until chopped.
Empty into skillet and repeat with remaining bread onion and stems. Saute' five minutes.
Put lemon juice, wine, parsley, salt, marjoram, thyme, and garlic powder into blender, cover and stir until mixed. Add to skillet, mix well and cook over low heat 5 minutes.
Place caps in a 9 x 13 pan, sprinkle with salt and monosodium glutamate, fill with bread mixture and bake 10 minutes. Turn oven control to broil and place mushrooms about 4inches from heat. Broil 4 to 5 minutes until golden brown.
Note: Mushrooms may be frozen after baking. To serve, broil about 9 inches from heat 8 to 10 minutes.