2In a large bowl, combine the lamb shoulder, beef sirloin, and chicken wings. Add finely minced garlic, grated ginger, light soy sauce, Shaoxing wine, sesame oil, 10 grams of cumin powder, 5 grams of chili powder, and white pepper. Mix well to coat all the meats. Marinate for at least 2 hours in the refrigerator, or preferably overnight.
3While the meats marinate, prepare the vegetables. Cut green bell pepper, red bell pepper, onion, and king oyster mushrooms into 2.5cm pieces suitable for skewering. Cut potato into 1cm thick slices. Blanch potato slices in boiling water for 2 minutes, then drain and pat dry.
