2 tbsp plain flour mixed with enough water into a paste
1 small egg, lightly beaten
Saute mushrooms and chicken in 2 tablespoons of oil. Add prawns, water-chestnuts and mix in seasoning. Stir-fry well to combine until chicken meat is cooked. Add thickening to mixture.
Dish out and add chopped spring onion. Set aside to cool.
Trim off sides from the slices of bread. Cut into triangular pieces. Put 11½ tablespoons filling onto a triangular slice of bread. Top with another triangular slice and press together lightly.
Press the edges of the bread together to seal in the filling. Brush lightly with a little flour paste. Dip the sides in beaten egg and coat with sesame seeds. Deep-fry the bread puffs until lightly golden.
Drain on absorbent kitchen paper towels and serve with chilli wasabe mayo sauce.