Savoury mung bean biscuits (Tau sar piah)

Instructions

1. To make the mung bean filling, place the mung beans in a clean bowl and pour over enough water to cover. Seal the bowl with plastic wrap and leave to soak overnight. The next day, drain the beans and rinse several times, then place in a lined steamer basket and steam for about 30 minutes until soft.
2. Meanwhile, heat the oil in a frying pan over medium heat. Add the shallot and fry for 1–2 minutes until golden and crispy. Remove with a slotted spoon, leaving the oil in the pan for later, and drain on paper towel.
3. Tip the beans into a sieve to drain off any excess liquid, then transfer to a food processor or blender. Add the fried shallot and blitz to a smooth paste, adding 1–2 tablespoons of the shallot oil if needed.
4. Reheat the shallot oil in the pan over medium–low heat and stir in the mung bean paste. Add the sugars and salt and cook, stirring, for another 2 minutes. Set aside to cool. Divide the cooled paste into 12 even portions and roll into balls. Store in a container until needed.
5. To prepare the water dough, place the flour and sugar in a bowl, add the shortening and rub it into the flour with your fingertips. Add 1½ tablespoons water and bring the mixture together to form a ball. Knead the dough on a non-stick surface for 1–2 minutes until smooth, then cover with plastic wrap and rest at room temperature for 1 hour.
6. Meanwhile, to make the shortening dough, place the cake flour and shortening in a clean bowl and mix together to form a pliable dough. Cover the dough with plastic wrap and set aside.
7. Divide the shortening dough into 12 equal portions and roll them into small balls. Repeat with the water dough.
8. Take one ball of water dough and use a rolling pin to roll it into a flat disc about 5 mm thick. Place one ball of shortening dough in the middle, then wrap the water dough around the shortening dough until it is completely covered.
9. Roll the combined dough into a flat oval shape and then roll it up like a Swiss roll. Roll it out again to a flat oval shape, then roll up like a Swiss roll. Roll it out to a flat disc about 5 mm thick and place one ball of the mung bean filling in the centre. Wrap the pastry around the filling to cover, then flatten it slightly at the bottom. Repeat with the remaining filling and pastry balls.
10. Preheat the oven to 180°C and line a baking tray with baking paper.
11. Place the pastries on the prepared tray, seam side down. Make an egg wash by whisking together the egg yolk and milk. Brush the pastries with the egg wash and sprinkle with sesame seeds. Bake for 20 minutes or until the pastries are cooked and golden brown. Allow the pastries to cool on the tray for about 15 minutes before transferring to a wire rack to cool completely. Store the tau sar piah in an airtight container at room temperature for up to 3 days.