Soak the dried shiitake mushrooms in warm water to rehydrate, then remove the hard ends of the stems and finely chop the rest.
Drain the tofu and pat it dry with paper towels. Slice the block in half crosswise, then cut each half into squares about ¾ inch (1.5 cm) thick.
Mince the ginger and the garlic. Thinly slice the chili. Separate the white and green part of the scallion. Thinly slice the scallion white and add it to the ginger and garlic, and cut the scallion greens into 2-inch long pieces.
In a small bowl, mix the light soy sauce, dark soy sauce and sugar until the sugar has dissolved. In another bowl, whisk the cornstarch with water to create a slurry.
Heat 2 tablespoons of the oil in a non-stick or well-seasoned pan over medium heat. Add the tofu slices in a single layer without crowding the pan. Fry each side for 4–5 minutes, until golden brown. Remove the slices from the pan and drain them on paper towels.
In the same pan, heat the remaining 1 tablespoon of oil. Add the douchi and fry it for 30 seconds. Add the ginger, garlic, chili, mushrooms and the white parts of the scallion and cook them for another minute, until fragrant.
Deglaze the pan with vegetable stock and bring it to a simmer. Add the soy sauce mixture and then the fried tofu, gently turning the slices to coat them in the sauce. Stir the cornstarch slurry to recombine it and add it to the pan. Cook everything for 2 minutes, until the sauce thickens. Toss in the scallion greens and serve immediately.
