How to Make It
In a medium bowl, whisk the rice flour with the coconut milk, egg, turmeric, half of the scallions and 1/2 teaspoon each of salt and black pepper. Whisk in enough tepid water (about 1 cup) for the batter to resemble thin pancake batter.
In a small bowl, whisk the fish sauce, sugar, vinegar, lime juice, Thai chiles and 2 tablespoons of water. Add one-third of the chopped red onion, and half each of the garlic and ginger. Stir in the carrots.
In a large skillet, heat the 2 tablespoons of vegetable oil. Add the remaining onion, garlic and ginger and cook over moderately high heat until softened, about 5 minutes. Add the pork, season lightly with salt and pepper and cook over high heat, stirring occasionally, until browned and cooked through, about 8 minutes. Stir in the remaining scallions. Transfer the pork to a bowl and keep warm.
Preheat the oven to 250°. Brush a small nonstick skillet or crêpe pan very lightly with oil and heat until very hot. Pour in about 3 tablespoons of the crêpe batter and swirl the pan to coat evenly with the batter. Cook over moderately high heat until the edge is just turning brown and the crêpe is nearly set, about 1 minute. Drizzle a few drops of oil around the edge and flip the crêpe to cook the other side, about 20 seconds. Turn the crêpe out onto a baking sheet and keep warm in the oven; repeat with the remaining batter to make 7 more crêpes.
Transfer the crêpes to a platter along with the lettuce leaves, sprouts and herbs. Serve alongside the pork, with the chopped peanuts and carrot-chile sauce in separate bowls. Wrap the crêpes and fillings in the lettuce leaves to eat.
Rice flour is made from ground white rice. It's available in Asian markets and health-food stores.