Peel and cube sweet potatoes. Place in a steamer and steam for 10 minutes until soft. Transfer to a large bowl and mash with a potato masher.

Add glutinous rice flour, white rice flour, granulated sugar, and baking powder to the mashed sweet potatoes.

Mix with a spatula until a soft dough forms. Dough should be soft but not sticky.

Spray a baking tray with vegetable oil spray. Preheat oven to 400˚F (200˚C).

Pinch a little dough from the bowl and roll between palms to form a 1-inch diameter ball. Place on prepared baking tray. Repeat until all dough is used up.

Spray formed sweet potato balls with vegetable oil spray. Bake in preheated oven for 10 minutes.

Remove baking tray from oven. Spray sweet potato balls with vegetable oil spray. Then flip sweet potato balls over. Return to oven and continue to bake for another 10 minutes.

Remove and serve warm.