Silken tofu and garlic chive soup

Ingredients

• 4 cup (1l) vegetable stock
• 2 cup water
• 200 gram bean thread noodles
• 300 gram silken tofu, drained, cut into 3cm squares
• 1 tablespoon sugar
• 1 teaspoon salt
• 1 bunch garlic chives, cut into 2cm lengths
• 150 gram bean sprouts
• 1/3 cup coriander leaves
• 1 tablespoon fried eschalots
• fish sauce, to serve (optional)