Deep fry the diced tofu until golden brown then set aside
Prepare the wok, pour cooking oil, then stir fry garlic and shallots until fragrant
Add both curly red chili and green chili, mix well
Once everything is half cooked, add tomato, mix well
Then add prawns and mushroom stock, stir well
Add fermented soybean straightaway so the prawns will get soaked by the flavour
Adjust with enough water, add sugar and sweet soy sauce to balance the saltiness from the fermented soybean
Lastly, add firm tofu. Stir well and cooked for another 10 minutes to have more depth of flavour