To make the bun dough, place the water, sugar and yeast into the Thermomix bowl and mix for 8 seconds, Speed 3. Allow to rest for 5 minutes or until the mixture has turned frothy.
Add the plain flour, olive oil, salt and baking powder into the Thermomix bowl and mix for 8 seconds, Speed 6 to combine. Knead for 10 minutes, Kneading Function.
Place the dough into a greased ThermoServer or large bowl and set aside in a warm, dry place to rise for 45 minutes.
Rip a piece of baking paper into strips and place over the 2 layers of the Varoma trays (leaving gaps in between to allow the steam to escape).
Knead the dough on an oiled bench or board. Divide the dough into approximately 15 - 18 small pieces. Roll into balls and flatten down into a circle/oval shape. Place small pieces of baking paper onto half of each flattened oval and fold over (so that the baking paper is in between.
Place the bao buns onto the 2 trays of the Varoma.
Fill the Thermomix bowl with 500g of water and put the Varoma (with the 2 trays) in place. Cook for 30 minutes, Varoma temperature, Speed 4.
Take the buns out (they will be quite wet and sticky) and serve immediately with leftover roast pork, slaw, Kewpie (Japanese) mayo and sesame seeds.