Chili Crab Flavored Fish Soup with Sourdough Mantou

Preheat your oven to 180°C (350°F). In a small bowl, combine the softened butter with a pinch of salt. Spread a thin layer of butter on each slice of sourdough.

Arrange the sourdough slices on a baking sheet and bake for 8-10 minutes, or until golden brown and crispy. These are your sourdough 'mantou'. Set aside.

Heat vegetable oil in a large pot over medium heat. Add the grated ginger, minced garlic, chopped red chilies, and thinly sliced shallots. Sauté for 2-3 minutes until fragrant and the shallots are translucent, releasing a spicy and aromatic fragrance.

Stir in tomato paste, chili sauce, oyster sauce, sugar, and light soy sauce. Cook for another 2 minutes, stirring constantly, allowing the flavors to meld and deepen.

Pour in the chicken broth and bring to a simmer. Let it simmer for 10 minutes to allow the flavors to fully develop and infuse the broth.

Gently add the fish cubes and prawns (if using) to the simmering broth. Cook for 3-5 minutes, or until the fish is cooked through and opaque and the prawns are pink and firm. Be careful not to overcook the fish, as it will become dry.

Slowly drizzle the beaten eggs into the simmering soup, stirring gently to create egg ribbons throughout the broth. This will add richness and texture.

Gradually add the cornstarch slurry (cornstarch mixed with water) to the soup while stirring continuously. This will thicken the soup to a desirable consistency.

Remove the pot from the heat and stir in the freshly squeezed lime juice. Taste and adjust seasoning as needed. Add more chili sauce for extra spice, or a pinch of sugar for sweetness.

Ladle the Chili Crab Flavored Fish Soup into bowls. Garnish with chopped cilantro. Serve immediately with the toasted sourdough 'mantou' slices for dipping and soaking up the flavorful broth.