Saute the mushrooms in butter for 10 minutes. use your own favorite batter or prepare the batter with 1/2 cup of flour and stir in one egg and one tablespoon of melted butter. Slowly stir in 1/2 cup of flat beer until smooth, then let the batter sit at room temperature for an hour.
Fold in one egg white (beaten stiff) and add the sauteed mushrooms. Drop the mushrooms, a few at a time, into a deep fryer set at approximately 350F and fry until golden. Salt and pepper to taste.