Baked Char Sui Bao (Cantonese BBQ Pork Bun)

Trim the pork loin to remove fat and tendon and slice lengthways so you have four long pieces, then cut in half. By cutting the pork in to smaller pieces to marinate you will end up with more flavoursome char sui. If you want to leave the pork in one piece you can do this as well. Place in container that you will be marinating them in.Combine all the other ingredients in a bowl and mix well to combine. Microwave the maltose in for a few seconds to make it easier to work with.Cover pork well with 3/4 of the marinade mixture. Marinate for a minimum of 4 hours, or overnight. Place the reserved 1/4 portion of the marinade covered in the fridge. You will use this as a baste when cooking the pork.Place marinated pork loin on the BBQ grill.Cook on a medium heat, approximately 15 minutes, until cooked through (145º), turning frequently and basting occasionally. Be careful to watch it closely so you don't burn the pork.*Made twice as much Char Sui as called for in the bun recipe, so I double the filling ingredients and froze half to make another day.Heat the vegetable oil in a wok or pan.Add diced char sui to the wok/pan and stir then add spring onions, cook for 1 minute.Add hoisin, dark soy sauce and sesame oil to the pork mixture, stir fry for one minute.Mix cornflour and stock together and then add to the pork mixture.Stir well and keep cooking until the mixture thickens, 1 or 2 minutes.Remove mixture from wok/pan and place in a bowl to cool. Set aside until ready to use.Place the sugar and warm water in a bowl, mix until the sugar has dissolved. Add yeast and leave it for 10 - 15 minutes until it becomes all frothy.Sift flour in to a large bowl.Add yeast mixture, egg, oil and salt and stir. Bring the flour mixture together with your hands.Place dough on a lightly floured surface and knead for approximately 10 minutes. The dough should be smooth and slightly elastic.Place in a lightly oiled bowl and cover with a damp cloth. Leave to rise until it is double in size. This will take from 1 - 2 hours depending on weather conditions.Once dough has doubled in size knock back and divide in to 12 portions and shape in to round balls.Use a rolling pin to roll out to approximately 5cm (2 inches) in diameter. Then pick the piece of dough up and gently pull the edges to enlarge to about 8cm (3 inches) in diameter. (By doing this it keeps the dough slightly thicker in the centre. This means when your buns are cooking they won't split on the top)Place a good sized tablespoon of filling on the dough circle. Then gather the edges and seal your bun.Place the bun seal side down on your baking tray. Continue with rest of dough.Once all buns are complete brush surface with egg wash.Place in a preheated oven of 400º F for 15 minutes or until golden brown.