Cut the Shan tofu into 1" cubes. Dice the tomatoes. Slice the red onion. Mince the garlic.
Heat 1 tbsp of oil over medium heat and fry the onions until translucent.
Add the garlic, tomatoes, turmeric powder, and chilli powder. Stir to mix well.
Add the water and bring to the boil. Then cover with a lid until the tomatoes become mushy.
Add the fish sauce, green chillies, and Shan tofu. Turn the heat down to low. Mix gently for 1-2 minutes.
Add 1 tsp garam masala and coriander, and mix gently until the coriander has wilted.
Serve hot with rice.