Make the dipping sauce:
-
Using a mortar and pestle, pound chiles, garlic, and sugar until mixture resembles a slurry, about 3 minutes. Stir in fish sauce, lime juice, and 2 tablespoons water until blended. Set aside.
Make the pancakes:
-
Whisk together rice flour and 2 1/4 cups cold water in a medium bowl. Whisk in scallion and turmeric until blended. Set aside.
-
Preheat oven to 200°F. Heat 1 1/2 tablespoons oil in a 10-inch nonstick skillet over high. Add 3 pork slices, 3 shrimp, and a few mushroom and onion slices. Sprinkle with 1/8 teaspoon salt and 1/8 teaspoon pepper. Cook until pork and vegetables are lightly browned, about 30 seconds per side.
-
Stir rice flour mixture. Remove skillet from heat. Holding skillet at an angle, pour in 1/3 cup rice flour mixture, and swirl to evenly coat bottom of skillet.
-
Return skillet to heat over medium. Cover and cook, undisturbed, until sides of pancake turn deep brown and curl up, about 5 minutes. Remove skillet from heat, and sprinkle 1/4 cup bean sprouts over pancake. Fold in half, and transfer to a baking sheet; keep warm in preheated oven. Repeat procedure with remaining oil, pork, shrimp, mushrooms, onion, salt, pepper, and bean sprouts to make 9 more pancakes. Arrange pancakes on a large platter, and serve warm with dipping sauce.