Put the pork in a roasting tin with the rest of the char siu ingredients and massage them in using your hands or a spoon to coat. Cover and keep chilled overnight.

Heat the oven to 160C/140C fan/gas 3. Cover the tin with foil and cook the pork for 3 hrs 30 mins, basting every hour. Turn up the oven to 180C/160C fan/gas 4, remove the foil, baste the pork and continue to cook for 45 mins until it is beginning to caramelise around the edges.

Remove the pork from the tin, cover and set aside to rest for 20 mins. Meanwhile, spoon off any fat and transfer the sauce to a small pan. Slice the pork – it will fall apart as you cut it – then return to the tin. Warm the sauce in the pan over a low heat, then pour over the meat and toss everything together.

While the pork is cooking, make the buns. Mix the flour, sugar and 1/2 tsp salt in a large bowl. Dissolve the yeast and a pinch of salt in 1 tbsp warm water, then add to the dry ingredients along with the milk, oil, vinegar and 200ml water. Mix into a dough using a wooden spoon, adding a little extra water if needed.

Tip the dough onto a lightly floured work surface and knead for 10-15 mins, or until smooth. Put in a lightly oiled bowl, cover with a damp cloth and leave to rise for 2 hrs, or until doubled in size.

Tip the dough out onto a clean work surface and lightly punch it down, then flatten and sprinkle over the baking powder. Knead for 5 mins.

Roll out the dough into a long sausage shape, about 3cm thick, then cut into 3cm-wide pieces – you should have 18. Roll each into a ball and leave to rest for 2-3 mins.

Use a rolling pin to roll out each ball into an oval shape 3-4mm thick. Rub the surface of each lightly with oil and brush a little over a chopstick. Put the oiled chopstick in the centre of each oval, fold the dough over the chopstick then slowly slide it out, leaving the dough folded over.

Transfer the prepared buns to a baking tray lined with baking parchment, then cover with a clean tea towel and leave to prove in a warm place for 1 1/2 hrs, or until doubled in size.

Heat a large bamboo steamer over a medium-high heat. Steam the buns for 8 mins or until puffed up (you’ll need to do this in batches). The buns are best served straightaway. The pork will keep in an airtight container for up to three days or frozen for up to a month.

Ease each of the buns open, then fill with the pork, carrot and mooli, spring onions and a dollop of the wasabi mayonnaise.