Browning the aromatics—ginger and shallots—and briefly cooking a few tablespoons of hoisin sauce, develops a solid flavor base for this simple soup. You can use flat, wide rice sticks or thin rice vermicelli. Either way, cook the noodles according to the package directions, then immediately divide them among individual bowls; if left to stand, the drained noodles may stick together. If you like, serve with lime wedges and Sriracha hot sauce.