½cuproughly chopped fresh cilantro leavesoptional, or to serve
Heat a large soup pot or Dutch oven over medium heat. Add the oil, and the onion, and sauté for 4 minutes until tender. Add the garlic, ginger and lemon grass sauté for 1 minute until you can smell the fragrance. Add the crushed chili, then pour in the broth and tomatoes, turn the heat to high, and bring to a simmer. Reduce the heat to medium low, and simmer for 5 minutes.
Stir in the chicken and rice noodles and return to a simmer. Add the spinach and the fish sauce, simmer for one more minute, then add the lime juice and cilantro (if using) and serve in shallow bowls.
You can use fresh lemon grass if you can find it, but you can also use lemon grass paste in a tube, or minced lemongrass, available in jars at specialty and Asian markets.
To cook rice noodles, bring a large saucepan of water to a boil. Break the noodles into 3-inch pieces (just for this recipe). Remove the pot from the heat, add the rice noodles and stir frequently for 3 to 5 minutes until they are fairly pliable, but not soft. Drain the noodles and rinse with cold water. Set aside. There are other methods, but this is a good one – check your noodle package for alternative directions.