Mix the flours, salt, and sugar together. Add the limewater and cold water, and stir until smooth. Set aside. Add the mussels to the batter and mix well.

Heat oil in a skillet over medium heat. When the oil is hot, pour the batter with mussels into the pan. Crack the eggs over the batter and spread them evenly. When the bottom is crispy, flip to cook the other side. While frying, spoon hot oil over the pancake until the batter is golden and crispy all over. (To get a crispy pancake, use plenty of oil, keep the batter thin, and fry until golden and crisp.) Move the pancake to the side of the pan. Remove some oil, add fried garlic, then add bean sprouts and stir-fry over high heat until just cooked. Season with soy sauce.

Transfer the bean sprouts to a plate. Place the fried pancake with mussels on top. Sprinkle with green onions, cilantro, and ground black pepper.

Serve with a simple sauce made by mixing equal parts sweet chili sauce and Sriracha.