Peel cooked potatoes, cut into ⅓” cubes, and marinate with salt for a while.
Prepare flour batter and mix with potatoes. Place potatoes into hot oil one after another, and deep-fry until golden brown. Deep-fry twice, cutting off irregular ends after the first time.
Saute diced onions and black mushrooms with 3 tablespoons hot oil, add catsup, ⅓ cup so