Soak the cellophane noodles in a bowl of hot water for 20 minutes. Then drain and cut them into bite-size pieces. In a medium bowl combine the shrimp, pork, onion, garlic, carrot, bell pepper, mushrooms, and green onion and mix well. Add the cellophane noodles, fish sauce, and chili garlic sauce and mix well. Set aside. The filling can be made up to 1 day ahead and kept, covered, in the refrigerator.

Fill a wide, shallow bowl with 2 inches of warm water, and place a damp paper towel or kitchen towel on your work surface. Immerse a rice paper wrapper in the warm water and soak it very briefly (just a few seconds—it will continue to soften as you fill it); then lay the wrapper on the damp towel. Place a tablespoon of the filling onto the bottom quarter of the rice paper and press it into a 2-inch-long line. Roll the bottom edge of the rice paper over the filling and then fold both sides inward, and continue tightly rolling the wrapper up like a burrito. Place the finished roll, seam side down, on a platter and cover it lightly with a damp cloth. Repeat the process with the remaining filling and wrappers.

Preheat the vegetable oil in a deep fryer to 350°F. Line a baking sheet with paper towels. Working in batches, fry the rolls, making sure that they do not touch one another while frying. The rolls will begin to bubble and hiss and the wrappers will begin to change texture. Cook the rolls, turning them as necessary for even cooking, until golden brown, 7 to 10 minutes. As they are cooked, transfer the rolls to the prepared baking sheet.

Serve the rolls with the lettuce leaves, herbs, and Thai-Style Sweet Chili Sauce.

Note : Banh trang is the Vietnamese name for rice paper wrappers. You may also see the French name, gallettes de riz, on the package.

Thai-Style Sweet Chili Sauce:

In a small saucepan, combine the sugar and water, stirring until the sugar has dissolved. Bring to a boil over medium-high heat, and then reduce the heat to a simmer. Let simmer for 5 minutes. Remove the pan from the heat, add the cilantro, and let the cilantro steep in the syrup for 15 minutes. Then strain the syrup, discarding the solids. Set aside and let cool completely.

Place the chiles, garlic, and fish sauce in the bowl of a mini chopper or mini processor and pulse to a coarse texture. Add the chile mixture to the cilantro syrup and bring to a simmer. Simmer for 8 to 10 minutes, until the mixture has reduced by half. The sauce should be slightly thick and will continue to thicken as it sits. Use immediately, or transfer to a jar and refrigerate. The sauce can be kept for up to 2 weeks in the refrigerator.