Mix the flours in a large bowl. Make a well and add the nam yue, salt, baking powder, sesame seeds and water.
Break the nam yue and mix it with the flour.
Mix in circular motions, drawing everything together until it is smooth.
Place dough in a bowl, cover with cling wrap and allow to rest for 2 hours.Dust the worktop with tapioca flour and flatten dough with a wooden rolling pin. Roll out into a sheet.
Wrap the dough sheet around the rolling pin to make a dough roll
Remove rolling pin
Use the rolling pin to press the dough roll evenly all over
Flatten the dough again and roll out into a sheet
Repeat the rolling and flattening steps twice more until the dough is very thin
Alternatively, use a pasta maker to flatten the dough until it is very thin.
Cut the dough into long strips and then into diamond shapes, about 5 x 1cm. Deep fry in hot oil until crisp and golden. Allow to cool completely and store in an airtight container. Keeps well for up to 2 weeks.