In a bowl, mix the flour with all the other ingredients up to and including the oil.
Knead for approx. 10 mins. to form a soft, smooth dough, cover and leave to rise for approx. 2 hrs. at room temperature until doubled in size.
Divide the dough into 12 portions and shape into balls, place each one on a piece of baking paper.
Flatten by hand to approx. 5 mm thick, brush with oil.
To steam, sit a steaming basket on a wide-bottomed pan. Fill with water until it is just below the bottom of the basket, place the dough balls in the steaming basket with the baking paper, cover and cook over a medium heat for approx. 10 mins.
Slice the avocado and cut the spring onions into strips. Tear the coriander.
Cut the meat into thin strips, remove the seeds from the chilli and chop finely. Finely grate the ginger.
Heat the oil in a non-stick frying pan. Brown the meat for approx. 1 min., grate in the ginger, add the chilli, sugar and soy sauce, heat gently and season with salt.
Gently press in the middle of the bao buns, fill with meat, avocado and spring onions. Tear the coriander, sprinkle over the top.