Steam the purple sweet potato for about 30 minutes until fork tender, peel, and mash the flesh unitl smooth and refined, add a small splash of soy milk if it's. a bit dry, each sweet potato. has different level of moisture so adjust accordingly;
In a microwave safe bowl, whisk together the glutinous rice flour and sugar, then slowly pour in the soy milk while continue whisking, until you reach a smooth batter with no lumps;
Cover the bowl with plastic wrap (I use a compostable one that's made of plant based biopolymers), poke 5-6 holes, microwave on high for 1 minute;
Stir the mixture, cover it back up and microwave on high for another minute;
Check on it, if it looks completely solidified then it’s ready, if not, microwave for another 30 seconds;
If you don’t have a microwave, you can steam the mixture covered by cling wrap for 30 minutes;
Add 1 tablespoon vegan butter to the mixture, fold and mix in with a spatula repeatedly, once it's not too hot anymore, oil your hands or wear food prep gloves to prevent sticking, take out the dough, stretch it out, fold, stretch again, repeat this process until you reach a soft smooth dough ball;
Dust your work surface with desiccated coconut, place down the dough, cover the top with more desiccated coconut, roll it out into.a rectangle about 1/4 inch thick;
If you're allergic to coconut, you can also use toasted glutinous rice flour instead, which also achieves the purpose of preventing sticking;
Spread the purple sweet potato paste evenly on top, then roll it up tightly;
The easiest way. to cut this roll is to use a piece of floss or embroidery thread, cut into your preferred slice thickness;
Serve immediately or keep in the fridge for up to 3 days, enjoy!
