Tom yum is a hot and sour soup from Thailand with lively notes of lemongrass, makrut lime leaves and galangal. There are many variations of this iconic soup, including tom kha (coconut milk and dominant galangal notes), tom yum pla (fish) and tom yum gai (chicken). This version is vegetarian, hence not traditional, but it is reminiscent of tom yum koong nam khon, a creamy version that uses canned evaporated milk. (Use coconut milk if you prefer). Tom yum is often moored by nam prik pao, a staple Thai chile paste of roasted chiles, shrimp paste and fish sauce, but in this recipe, a combination of soy sauce, lime, garlic and sambal oelek provides a similar umami kick. The addition of vermicelli and tofu is also unconventional, but it turns this soup into a hearty, quick and comforting weeknight dinner.