Steam 1 sweet potato in a steamer with the lid on for 10–15 minutes starting with cold water.

Peel the steamed sweet potato and mash it well.

Mix the mashed sweet potato with 1 tbsp sugar and 3 tbsp potato starch to form a dough. Adjust sugar based on the sweetness of the sweet potato.

Shape the dough into flat, round pieces and place about 1 tbsp of mozzarella cheese in the center. Seal the edges to enclose the cheese.

Heat a pan over medium-low heat, add cooking oil, and pan-fry the cakes until golden brown on both sides.

For a sweeter version, heat 3 tbsp cooking oil and 4 tbsp sugar in a pan over medium heat until the sugar melts completely.

Turn off the heat, add the fried cakes to the pan, and coat them well with the melted sugar.