Soak dried mushrooms until soft then dice.
Boil dried beancurd puffs, water chestnuts, bamboo shoots in hot water, then dice.
Cut celery into fine dices.
Heat oil in wok, fry all ingredients for filling, add in seasonings, stir well until ingredients are cooked, then thicken sauce with cornstarch solution. Add in mashed potato and stir until almost dry. Take out and reserve.
Cut bread slices into half circles, pat some cornstarch onto sides. Place fillings on bread and top with another slice of bread. Press firmly, and coat sides with breadcrumbs.
Heat oil and wine in wok, then put in filled breads and fry until golden brown.