Make the batter: In a large bowl, whisk together the rice flour, cornstarch, turmeric powder, and salt. Make a well in the center, pour in the coconut milk, beer, and 1 ½ cups|355 ml warm water, and whisk until smooth. Whisk in the scallions and set the batter aside to rest for 1 hour.

Make the nuoc mam cham: Dissolve the sugar in the lime juice, fish sauce, and ½ cup|125 ml water. Stir in the garlic and chilies and set aside.

Make the filling and the crepes: Place the mung beans in a small saucepan and add enough water to cover. Bring to a boil, then reduce the heat to maintain a simmer and cook until soft, about 5 minutes, then strain.

Heat 2 tablespoons oil in a large nonstick skillet over high. Add 3 to 4 pieces of pork, 2 to 3 shrimp, and ⅓ cup|30 grams sliced onion and cook, stirring occasionally, until the pork and shrimp are golden and cooked through, about 3 minutes. Season with the fish sauce, sugar, salt, and pepper and push the mixture to one side of the skillet.

Pour ½ cup|125 ml batter into the skillet, swirling to cover the bottom. Cook until partially set, about 45 seconds. Sprinkle 1 to 2 tablespoons mung beans over the crepe and a heaping ⅓ cup|35 grams of the bean sprouts. Lower the heat to medium, cover, and cook until the bean sprouts have wilted slightly, about 3 minutes.

Uncover and drizzle 1 to 2 teaspoons oil around the rim of the skillet. Cook, uncovered, until the edge of the crepe crisps and pulls away from the rim of the skillet and turns golden brown, about 2 minutes more. You may need to pop the heat up a bit more or down at this stage (everyone’s stovetops and pans are a bit different!).

Fold the crepe in half with a spatula and slide it onto a serving platter. Keep warm. Wipe the skillet clean and repeat with more filling and batter to make 5 crepes.

To serve, pass the platter of crepes with the garnishes and dipping sauce. Tear off a piece of the crepe, wrap it with lettuce and any combination of the herbs, and dip in nuoc cham.