FOR THE BAO BUNS: PREPARING THE DOUGH
Dissolve the brewer's yeast in a bowl containing the water and milk at room temperature.
Next add the sugar, seed oil, and the baking soda dissolved in the apple cider vinegar.
Now add the sifted flour and knead to a dough in a planetary mixer at low speed (or by hand).
After a few minutes, add the salt dissolved in a few drops of water.
Transfer the dough onto a lightly floured pastry board and knead until smooth to the touch.
Place in a bowl greased with oil and cover it with cling film, then leave to rise for about one and a half hours or until the dough has almost doubled in volume.
PREPARING AND COOKING THE BUNS
Once the bao dough has risen, roll into a long rope and divide it into 6 pieces.
Form 6 balls and use a rolling pin to roll them out into a slightly oval shape.
Place a piece of baking paper on one side and fold the dough over to form a half-circle shape.
Steam for about 25 minutes after covering the steamer basket with perforated baking paper.
Store the bao buns wrapped in a tea towel so that they stay moist.
PREPARING AND SEASONING THE ROAST BEEF
Rub the meat with the chopped herbs, salt and pepper.
Heat a large frying pan with a little oil and garlic.
Place the roast beef in the pan and brown it briefly all over.
Once browned, place the meat with all its juices in an oven dish and roast in a preheated oven at 200°C for about 5 minutes, then reduce the temperature to 180°C and roast for a further 10 to 15 minutes.
Regardless of the time, check the core temperature of the meat with a probe: it needs to be between 48° and 52°C.
Remove the meat from the oven and wrap it with baking paper and then aluminium foil.
Collect and strain the cooking juices, then pour them into a saucepan together with the balsamic vinegar. Cook over a medium heat until reduced.
Once cooled, slice the roast beef thinly and drizzle with the balsamic vinegar sauce.
PREPARING THE ONIONS
Finely slice the onion and marinate it in a bowl filled with equal parts water and white wine vinegar. If you like, add a teaspoon of hibiscus powder to give it a nice pink colour, and 2 teaspoons of sugar.
Leave to marinate for at least 2 hours.
ASSEMBLING AND SERVING THE BUNS
Remove the baking paper from the bao, insert a lettuce leaf, two slices of roast beef seasoned with balsamic sauce and a few slices of marinated onion.
Garnish with mayonnaise, salt flakes and serve immediately.
