Add the rice flour, tempura flour, and arrowroot starch to a mixing bowl. Pour in the ice-cold water and stir until smooth. Add the mussels and green onions, then mix well.

Heat a skillet over high heat. Pour in the oil. Once the oil is hot, add the batter with mussels and spread it evenly in the pan using a spatula.

Crack the egg into the center and break it up slightly. Continue frying until the bottom is golden and crispy, then flip it over.

Move the pancake to the side of the pan. Add the bean sprouts and stir-fry until just softened.

Transfer the bean sprouts to a plate, then place the mussel pancake on top. Sprinkle with green onions, cilantro, and ground black pepper.

Mix the chili sauce and sweet chili sauce together to make the dipping sauce. Set aside.

Serve the crispy mussel pancake with the dipping sauce. Enjoy!