Heat a nonstick wok or large frying pan over a high heat and add half the oil. Add the aubergine and stir-fry for about 5–6 minutes until browned and softened. Add the measurement water and cook for 1–2 minutes. Transfer the aubergine to a plate and set aside.
Add the remaining oil to the pan and heat over a high heat. Add the garlic, ginger and chilli and stir, then add the chilli bean paste and stir-fry for 30 seconds.
Pour in the hot stock, return the aubergine to the pan along with the tofu and bring to a simmer. Add the soy sauce, vinegar and sugar, then stir in the spring onions and the cornflour paste and cook, stirring constantly, for about 3–4 minutes until the mixture has thickened. Scatter with spring onions and serve with steamed rice.