Heat 1 tablespoon ground nut oil in a wok over high heat. Add the 3 ginger slices and 8 spring onion slices, frying for about 1 minute until fragrant. Toss in the 1 red pepper and continue to fry for another 1 minute, just until it starts to soften a bit.
Next, add the 85g water chestnuts and 100g bean sprouts, tossing everything together until the bean sprouts begin to wilt. Finish with 1 tablespoon soy sauce and a generous grind of black pepper, then transfer the cooked vegetables to a serving dish.