1. Heat oil in a pan and sauté char siu, mushrooms, onions and yellow chives. Stir in sauce mix and cook until thickened. Set aside to cool and divide into 8 portions.
2. Cut each sheet of puff pastry into 4 quarters. Place filling into a pastry quarter and wrap to make a triangle. Glaze each pastry with egg wash. Sprinkle sesame seeds then put the puff on a baking tray.
3. Preheat oven at 180℃. Bake pastry for 15 minutes until golden brown. Garnish and serve hot.