No fresh lemongrass? It can be purchased in a tube in the produce department called Gourmet Garden, but if pushed, you can substitute an equal amount of lemon zest. Warm lemongrass-scented stir-fried shrimp contrast with the cool rice noodles, crunchy bean sprouts, and cucumbers in this one-dish meal, making an especially refreshing summer supper. A recipe from Mai Pham.