1 egg yolk, beaten with ¼ tsp water and a pinch of salt
For the filling: Mix the lotus paste with diced dried longan then scale the filling into 130g pieces. Wrap 5g of chicken floss in the centre. Shape this filling into a round ball.
Mooncake skin: Put golden syrup into a mixing bowl. Stir in alkaline water and bicarbonate of soda then mix in corn oil.
Leave aside for one hour. Sift in 280g of superfine flour and mix into a dough. Cover with cling film and set aside for 2-3 hours to rest. If dough is still sticky and too soft, add in the extra flour to mix.
Scale the dough into 45-50g portions. Roll out each portion and wrap around a piece of filling.
Dust a mooncake mould with some flour, then knock out the excess flour.
Press the prepared portion of dough into the mooncake mould. Knock the sides of the mould gently to dislodge the mooncake. Place it on a lightly greased tray.
Bake in a preheated oven at 180°C for 10 minutes. Remove mooncakes from the oven and brush with egg wash. Return the mooncakes to the oven and continue to bake for 10 minutes more.