Cut the potatoes into bite-sized pieces and soak them in water for 5 minutes. Drain and place them in a microwave-safe bowl. Microwave at 600W for 4 minutes, then mash them with a fork while hot, adding a pinch of salt.

Add potato starch to the mashed potatoes and mix well. Divide into 10 portions and shape into small balls.

Heat vegetable oil in a frying pan over medium heat. Place the potato balls in the pan and fry, rolling them around to evenly brown all sides. Remove from the pan once golden.

Wipe the pan clean and add the sauce ingredients (soy sauce, sugar, potato starch, and water). Stir and heat over medium heat until the sauce thickens.