Sour Fish Soup

Fillet the fish and reserve the head, bones and scraps. Cut the fillets into 1-inch cubes and place in a bowl with the fish sauce, pepper and green onion. Toss gently to mix, then let marinate at room temperature while you make the soup.

FOR THE SOUP: In a large saucepan over medium heat, warm the oil. When the oil is hot, add the shallots, lemongrass, and the fish head, bones and scraps; sauté gently without browning until fragrant, 3-5 minutes. Add the water or chicken stock and bring to a boil. Reduce the heat to low and simmer the stock uncovered for 20 minutes.

Meanwhile, in a small bowl, soak the tamarind pulp in the boiling water for 15 minutes. Mash with the back of a fork to help dissolve the pulp. Pour through a fine-mesh sieve into another small bowl, pressing against the pulp to extract as much flavorful liquid as possible. Discard the pulp and set the liquid aside.

Pour the stock through a fine-mesh sieve into a large saucepan. Discard the contents of the sieve. Bring the stock to a boil. Stir in the tamarind liquid, pineapple, bamboo shoots, chilies, sugar and fish sauce. Reduce the heat to medium and simmer for 1 minute. Add the tomatoes and fish cubes and continue to simmer until the fish turns opaque and feels firm to the touch, 3-5 minutes. Add the bean sprouts and season to taste with salt and pepper.

TO SERVE: Ladle the soup into warmed soup bowls and garnish with cilantro or mint. Serve with lime wedges.