Put the mushrooms in a small heatproof bowl and pour over 300ml freshly boiled water. They’ll do their best to float, but immerse them by pressing them down with a spoon or gently pressing the base of another bowl on top.
Leave for 10 minutes, then squeeze out the mushrooms into the bowl, and finely slice the flesh; put both the liquid and mushrooms to one side.
In a separate little bowl, mix the cornflour with two tablespoons of the mushroom stock, then add the Shaoxing wine, both soy sauces and the sugar, stir and put to one side.
Once you’ve pressed all the water from your tofu, cut it into 1.5cm slices. In your widest nonstick pan for which you have a lid, heat two tablespoons of oil over a medium heat and, when very hot, add the tofu slices in a single layer.
Leave to fry for three to five minutes, until golden then flip over with a spatula and fry the other side. Transfer to a plate and set aside.
In the same pan, on a medium to high heat (add a little extra oil, if need be) add the ginger, garlic, spring onions and chillies and fry for about four minutes, until fragrant.
Turn down the heat, then add the cornflour and soy sauce mixture, the sliced mushrooms and their reserved stock (save for the final teaspoon or two, which may contain some grit), and stir to combine.
Bring to a boil, then return the tofu slices to one side of the pan and put the shredded pak choi on the other side.
Cover the pan, leave for five minutes until the tofu is hot and the greens tender, then take off the heat.
Distribute across four plates and serve with freshly steamed or boiled rice.
