Cook the noodles in boiling water for 1 minute, until just tender. Drain well, cool in cold water, and then drain well again. Divide the noodles among 4 large, shallow bowls. Arrange the remaining ingredients, except the nuoc cham, artfully on top of the noodles. Serve each bowl of noodles with a bowl of the nuoc cham for drizzling on top.
Note: Nuoc cham is Vietnamese-style dipping sauce. To make it, combine 1/2 cup hot water and 3 Tbsp. granulated sugar in a bowl. Mix in 1/4 to 1/2 tsp. crushed chili flakes, 1 crushed garlic clove, 3 Tbsp. fish sauce, 2 Tbsp. lime juice and 1/4 cup grated carrot. Steep 15 minutes before serving. Can be made ahead and stored in the fridge until needed.
Recipe Options: Instead of topping the noodles with cold, cooked prawns, you could top each bowl with 2 hot spring rolls, sliced into bite-sized pieces. Ready to heat-and-eat spring rolls are available in the frozen foods aisle. If you like beef, slice and top the noodles with the hot steak featured in this website collection recipe: Asian-Style Beef, Noodle and Green Onion Soup.