In a large bowl, combine the grated sweet potato, flour, cornstarch, baking powder, salt, and black pepper. Mix well.
Add the cold water gradually, stirring until the batter is smooth and well combined.
Fold in the shrimp, green onions, and cilantro until evenly distributed.
Heat about 1/2 inch of vegetable oil in a large skillet over medium-high heat.
Once the oil is hot, drop spoonfuls of the batter into the skillet, flattening them slightly with the back of the spoon.
Fry for about 3-4 minutes on each side, or until golden brown and crispy. Remove and drain on paper towels.
Serve hot with a dipping sauce of your choice.