Open sesame: banana and sweet potato provide the starch. Pic Michael Fountoulakis

Ingredients

100g dried mung beans

140 g sugar

A few drops of vanilla extract

1 sweet potato

1 banana

180 g glutinous rice flour

40 g sesame seeds

Vegetable oil, for deep-frying

Method

To make the doughnut filling, rinse the mung beans under cold running water and place in a bowl. 

Cover with cold water and allow to soak for 2 hours. Drain the mung beans well. 

Place in a steamer set over a saucepan of boiling water and cook for 20 minutes, or until soft.

ransfer the mung beans to a dry wok or frying pan. Add half the sugar and dry-fry over low heat until the sugar has dissolved. 

Remove from the heat and stir in the vanilla. Divide the mixture into 40 portions and shape into small balls.

Peel the sweet potato and steam it whole for 15 minutes, or until soft. Weigh out 120g of both the sweet potato and banana. 

Place in a mortar and pound until smooth. Sift the flour into a bowl. Add the remaining sugar and 2½ tbsps warm water and mix to combine. 

Now add the mashed sweet potato and banana and lightly knead for 3-4 minutes, until you have a smooth dough. 

Cover with a damp cloth and leave to rest for 20 minutes.

Divide the dough into 40 equal portions, roughly the size of golf balls. Take one piece of dough at a time and flatten it into a disc. 

Place a mung bean ball in the middle, then encase it in the dough. 

Roll in the palm of your hands to form a ball, then dip the doughnut in the sesame seeds. 

Repeat with the remaining ingredients. Heat about 10 cm (4 inches) of oil in a wok. 

To test the oil, place the tip of a wooden chopstick into the oil – when bubbles slowly rise to the surface, the oil is hot enough to use.

Fry the doughnuts in batches for 4-5 minutes per batch, until golden brown. Drain well on paper towel and eat while still warm.

Recipe from ‘Made in Vietnam’ by Tracey Lister & Andreas Pohl 

Check out this Salted Fish Fried recipe for more flavours from Vietnam