Put the first nine ingredients in a saucepan and bring to the boil (this is your stock). Simmer for 15-20 minutes over low-medium heat. Remove from the heat and strain. Reserve the stock and discard the rest.
Heat the oil in a large saucepan and sauté the Soup Paste for a minute until fragrant. Add the tofu, shiitake and button mushrooms and stir-fry over high heat for 1 minute.
Bring the prepared stock to a boil. Turn the heat to medium and add the sautéed tofu and mushrooms, the soy sauce, sugar and lemon juice. Simmer for 5-6 minutes over medium heat until the mushrooms are tender.
Sprinkle the coriander and basil and remove from heat. Serve hot.
