Chinese doughnuts (Ngau lei so)

Instructions

1. To make the starter, mix together 100 g of the flour and 100 ml tepid water. Place in a clean container, cover and leave to ferment at room temperature for 1 day. Feed with 25 g flour mixed with 25 ml (1 fl oz) water, cover and leave for another day.
2. To make the water pastry, place the sugar in a large bowl, add 160 ml tepid water and stir until dissolved. Add the baking soda, salt, alkaline water and starter and mix well, then add the flours and mix to form a dough. Mix in the bowl for 10 minutes (or use a stand mixer fitted with a dough hook). The dough will still be quite sticky at this stage. Cover and rest in the bowl for 10 minutes. Turn out onto a clean bench and knead the dough for a further 5–10 minutes. Cover with plastic wrap and rest for 15 minutes.
3. Roll the dough into a square about 3 cm thick, fold it in half from left to right, and then fold it in half again from top to bottom. Cover with plastic wrap and rest for another 30 minutes.
4. Meanwhile, prepare the oil pastry. Dissolve the sugar in 65 ml tepid water, then add the baking soda and oil and mix well. Add the starter and cake flour and stir until combined - cover and rest for 10 minutes. Knead in the bowl for 5 minutes, then turn out onto a clean bench and knead for another 10 minutes, sprinkling with more flour if necessary. Cover with plastic wrap and rest for 15 minutes.
5. On a lightly floured surface, roll out the water pastry to a 30 cm square. Roll out the oil pastry to a 30 cm x 15 cm rectangle.
6. Position the oil pastry on top of the water pastry (in the middle), then pinch down the edges of the oil pastry to secure it to the water pastry.
7. Fold the water pastry over the two long sides of the oil pastry and pinch the meeting point to secure. You should now have one 30 cm x 15 cm rectangle, about 2.5 cm in height. Position the dough with the longest side closest to you, then cut it into ten 15 cm x 3 cm strips.
8. Turn all the strips on their sides so the cut sides face up, then, if necessary, gently roll so the strips are all similar in height.
9. Pour the oil into a large wok and heat over high heat until it reaches 160°C or until a cube of bread dropped in the oil browns in 30–35 seconds. Reduce the heat to medium.
10. Working in batches of three or four at a time, add the dough strips and cook for 1 minute on each side. Keep turning and frying for another 4–5 minutes until the dough has puffed up and is golden brown. Remove with a slotted spoon and drain on paper towel. Dust with icing sugar and serve the doughnuts warm. Will keep in an airtight container for up to 2 days.