Peel the sweet potatoes, wash them, cut into small pieces, and steam until cooked.

Place the sweet potatoes in a bowl and mash them until smooth. Then add the glutinous rice flour, rice flour, butter, and sweetened condensed milk to the bowl and mix well.

Flatten each ball and place a little grated cheese in the center. Roll the dough back into a ball.

Roll the sweet potato balls in beaten egg, then coat with breadcrumbs.

Repeat with all the ingredients. Heat a pan with oil, and when hot, fry each sweet potato ball until golden and crispy. Remove and drain on paper towels.

Arrange on a plate and serve hot with ketchup or hot sauce. Remember to eat them hot so the cheese can stretch!