Mix together the warm hot, with the sugar and yeast until dissolved and set aside. Place the flour and vegetable oil into a large mixing bowl, and mix through the water mix.
Place in a freestanding mixer with a dough hook attached and knead into a rough dough. Then knead until it's smooth and springy, about 10 minutes. Rest the dough for 10 minutes.
On a floured surface, roll the dough out to form a long rectangle. Fold one end into the middle, then pick up and fold the other end into the middle. Reroll into a rectangle then roll into a sausage shape starting with the shortest end.
Cut into 12 rolls and place on individual pieces of greaseproof paper. Fill your steamer with cold water. Place the rolls into the steamer and allow it to rise for 20 mins then turn the steam on and let them do their thing.
Steam the buns for 15 minutes. Whilst you are waiting for heat the frying oil to 180. Add the steamed buns to the oil for a minute until golden all over.
Place a wok in high heat with a tbsp sesame oil and add in the crab. Stir fry for 2-3 minutes. To this add in the chillies, garlic and ginger and cook for a further minute.
Add in the remaining sauce ingredients and cook for a further 4 minutes, turning the heat down if need be.
Heat veg oil to 180 to deep fry the buns and once light and goldenrod serve with the chilli crab, they can be filled or used to mop up the saucy crab.