To begin, fry the tofu*. You can skip this step if using tofu puffs, or you can simply add raw tofu to the soup, to heat in the broth (this is safe to eat). If you want to fry your own tofu, pre-heat the oil to 180 degrees Celsius (356 Fahrenheit). Cut the tofu into cubes or triangles, and put them into a bowl. Sprinkle over cornflour and gently shake the bowl to cover. Once the oil is hot, gently add the tofu and fry until golden brown. Drain on kitchen paper and set aside until later.

Make the broth. Add 1 liter water to a large stockpot along with a vegetable stock cube***. Take the outer layer off the lemongrass and cut it into two, and tear the kaffir lime leaves. Add these to the broth along with galangal, garlic cloves, shallot, and chili paste. Stir well, set to medium heat, and bring to a boil.

Strain the broth. Once the broth has boiled, strain it into another pan through a metal sieve or cloth. Discard the aromatics, and put the clear broth back on to cook.

Season the broth. Season the clear broth with black pepper, brown sugar, lime juice, dark soy sauce, vegetarian fish sauce, and salt (taste before adding, as vegetarian fish sauce is sometimes extremely salty). Taste the broth and if needed add more chili paste, lime juice, or vegetarian fish sauce.

Cook the vegetables. Once the broth is seasoned to your taste, add a large tomato, quartered, carrot, green beans, and mushrooms. Cook until the vegetables are al-dente, or with a slight bite. This should take about 5 minutes.

Finish the soup. Turn the heat to the lowest setting and add the coconut milk and tofu.

To make the noodles, add to a large, heatproof bowl or saucepan and pour over enough boiling water to cover completely. Leave them to sit for 2 minutes, then drain.

Assemble the Tom Yum soup. Add a portion of noodles to a boil and ladle over the soup. Garnish with fresh cilantro, green onions, red chilis, and a wedge of fresh lime (optional).

Serve with fried rice crackers on the side for extra crunch.