Purple Sweet Potato Angkoo Kuih with Mung Bean Paste Filings

I have made Angkoo kuih from orange sweet potatoes before (see recipe in August 2018) and I just got to try making them from the purple sweet potatoes. The purple sweet potatoes are harder to find in the market. When steamed they are harder and drier in texture. However, the taste of the Angkoo kuih made from the purple sweet potatoes are the same as those made from the orange ones. The colours of both the purple and orange Angkoo kuih are equally vibrant. 

Ingredients:

For the base:

• banana leaves
• some cooking oil (I use corn oil.)

For the fillings:

• 200 g mung beans
• 100 g castor sugar (Can be reduced to 80 g for those who do not want to take too much sugar.)
• 2 - 3 pandan leaves
• 100 ml water
• 4 - 5 tbsp shallot oil

For the dough:

• 300 g purple sweet potatoes
• 250 g glutinous rice flour
• 1 tbsp rice flour
• 160 - 180 ml hot water

Method:

For the base:

• Cut the banana leaves according to the size of your mould. My mould measures 6 cm x 6 cm so I have cut the leaves into 7 cm x 7 cm sq. - approximately 60 pieces (30 pieces to be used prior to steaming and the remaining 30 pieces for changing the leaves after steaming.
• Wash the cut banana leaves and wipe them dry.
• Grease the banana leaves with cooking oil so that the dough doesn't stick onto the leaves.

For the fillings:

• Wash and soak mung beans for about 3 hours.
• Put the mung beans into a metal plate.
• Wash and cut the pandan leaves into 6-7 cm length.
• Place the pandan leaves in between the mung beans.
• Bring water to boil in a steamer.
• Place the metal plate in a steamer and steam the mung beans for an hour or until the beans are soft.
• Once the beans are soft, transfer them into the food processor.
• Blend the beans with water, sugar and shallot oil until the beans are fine.
• Pour the beans mixture into a non-stick pan and fry them until it becomes a thick paste which can be rolled into a ball.
• Remove from the fire and let the mixture cool down.
• Once the mixture has cool down, shape them into balls. The weight of your fillings depends on the size of your mould. With my 6 cm x 6 cm size mould, I made the filling  into 12 g so that when it is wrapped inside the dough, the whole dough ball with the filling will fit nicely into the mould. So, you have to experiment a bit before deciding on the weight of your filling.
• Once the fillings have been shaped into balls of the size that you want, cover them with a damp towel and set them aside until you need to use them.

For the dough:

• Wash and cut the purple sweet potatoes.
• Place them into a metal plate.
• Bring water to boil in a steamer.
• Once the water has boiled, place the metal plate of purple sweet potatoes into the steamer.
• Steam until the sweet potatoes are soft.
• Remove the sweet potatoes from the steamer and mash them while they are hot.
• Put the glutinous rice flour and the rice flour into a mixing bowl.
• Put the mash sweet potatoes into the mixing bowl. Use a spoon and mix the sweet potatoes and the flours until well combined.
• Add in hot water, bit by bit, until they can be shaped into balls. To fit my mould, the weight of my dough ball is 24 g. So, you have to experiment to get the weight which can fit into (with the filling wrapped inside) your mould nicely.

Assembly:

• Take a piece of dough ball, flatten it and put the filling onto it. Slowly bring the flattened dough to cover the filling and roll it back into a ball.
• Dust the mould with glutinous flour.
• Place the ball into the mould and press it down to cover the mould nicely. If there is any dough higher than the mould, it means that the dough is too big. So, you have to adjust accordingly.
• Knock the wooden block of the mould on a table. The dough will easily drop off if you have dusted the mould well.
• Place the moulded dough on the greased banana leave.
• Repeat this until all the dough balls and filling balls are finished.
• Bring the water in the steamer to boil.
• Once it has boiled, place all the moulded dough onto the steamer rack.
• Steam the moulded dough over high heat for 4 minutes. Open the steamer cover, quickly brush the dough with some cooking oil. Once completed, cover the steamer and continue to steam the dough at high heat for another 4 minutes. This process will help to maintain the design of the kuih. (I used to steam them for 10 minutes over high heat. But I have since reduced the duration to 8 minutes as I found that the dough have cooked by then.)
• Remove the kuih from steamer and let them cool down completely.
• Remove the kuih from the banana leaves and place them onto fresh ones. Cut the banana leaves around the kuih.
• The angkoo kuih are ready to be served.