
Experience the bold, vibrant flavors of Thailand with this authentic Tom Yum soup. A perfect balance of spicy, sour, and savory, this aromatic broth is infused with lemongrass, galangal, and kaffir lime leaves for a truly soul-warming meal.
Prepare the shrimp by peeling them and removing the heads. Reserve the shrimp meat and the shells/heads in separate bowls.
Heat 1 tablespoon of vegetable oil in a wok or large pot over medium-high heat. Add the shrimp shells and heads, stir-frying for 1-2 minutes until they turn a bright, deep orange. Pour in 3 cups of water and bring to a simmer. Cover and simmer for 10 minutes to extract the flavor. Strain the stock into a clean pot, discarding the shells, and stir in the chicken stock.
Prepare the lemongrass by trimming away the dry, reedy top and the base. Peel off the tough outer layers to reveal the tender core. Bruise the lemongrass using a mallet or the back of a heavy knife to release its aromatic oils.
Cut the bruised lemongrass into 2-inch (5 cm) lengths and add them to the broth. Add the shallots, cilantro stems, galangal slices, kaffir lime leaves, and Thai chilies.
Bring the broth to a simmer, cover, and cook for 10 minutes. For a traditional Thai presentation, leave the aromatics in the pot, or remove them with a fine-mesh strainer if you prefer a clear broth.
Add the mushrooms and simmer for another 5 minutes. Stir in the sugar, Thai chili paste, and fish sauce, ensuring the chili paste is completely dissolved.
Add the reserved shrimp meat to the soup and simmer for 30 seconds to 1 minute, depending on their size, until they are just cooked through and opaque.
Place the fresh lime juice into your serving bowls rather than the pot. Ladle the hot soup over the juice. This preserves the fresh acidity of the lime and protects the seasoning of your wok from the acid.
Garnish with fresh cilantro leaves and serve immediately while piping hot.
For a creamier version known as Tom Yum Nam Khon, stir in a splash of evaporated milk or coconut milk just before serving. If you cannot find fresh galangal, look for dried slices; avoid substituting with ginger as the flavor profile is significantly different.