Whisk the rice flour, turmeric, and salt in a large bowl. Slowly pour in the coconut milk and water, whisking until the batter is completely smooth and resembles heavy cream. Let the batter rest for at least 30 minutes so the flour can fully hydrate for a crispier result.

Whisk the lime juice, sugar, water, soy sauce, garlic, and chili in a small bowl until the sugar dissolves. Set the dipping sauce aside to let the flavors meld.

Heat a tablespoon of oil in a 10-inch nonstick skillet over medium-high heat until it shimmers. Add the mushrooms and tofu and cook, stirring occasionally, until the mushrooms are browned and the tofu is lightly golden, about 5–7 minutes. Transfer the mixture to a bowl and wipe out the skillet.

Return the skillet to medium-high heat with a teaspoon of oil. Stir the scallions into the rested batter. Pour a portion of the batter into the center of the pan and immediately swirl to coat the bottom and slightly up the sides; the batter should sizzle loudly and develop small lacy holes as it hits the heat.

Scatter a portion of the mushroom mixture and sprouts over one half of the crêpe. Cover the pan and cook until the sprouts have slightly softened, about 2 minutes.

Remove the lid and continue cooking until the edges of the crêpe are deeply golden, crisp, and start to pull away from the sides of the pan. Fold the crêpe in half over the filling and slide it onto a plate. Repeat with the remaining oil, batter, and filling.

Serve immediately while the crêpe is still hot and crackling, accompanied by lettuce leaves and fresh herbs for wrapping and the dipping sauce for dunking.