1.Add the oil to a deep-fryer or to a 15-centimetre depth in a large pot and heat to 170C.
2.For the chilli sauce,add all the ingredients to a saucepan and simmer for four minutes,until the sauce thickens slightly. Tip into a large bowl.
3.Whisk the egg whites in a large bowl until foaming. Whisk in 200 millilitres of water and the salt. Sift in 50 grams of rice flour,the potato starch,plain flour,baking soda and ground pepper and mix until you have a smooth batter.
4.Dust the chicken in the remaining 50 grams of rice flour and add to the batter. Toss through until well coated.
5.Fry the chicken in batches for seven minutes each. Drain on paper towel and set aside,keeping the batches separate.
6.Once all the chicken has been cooked,fry again for another seven minutes,starting with the first batch you cooked,until golden and cooked through. Drain again and keep warm.
7.Once all the chicken has been cooked a second time,add to the sauce and toss until thoroughly coated. Serve with a sprinkling of sesame seeds and spring onion.
TIPS
1.Don't worry about the batter clumping rather than coating the chicken evenly;it gives the chicken plenty of crunchy,irregular edges to take up the sauce.
2.Dusting the chicken properly in rice flour helps the batter cling to the chicken.
3.It's important to add the cooked chicken to the sauce all in one go. If you add the chicken bit by bit,the first batch can soak up more sauce than it needs,leaving the last a little short.