01 - Heat 1 tbsp of vegetable oil in a large skillet or wok over medium-high heat. Add garlic and ginger, sauté for 30 seconds until fragrant.
02 - Add cabbage, carrots, mushrooms, and bell pepper. Stir-fry for 2–3 minutes until slightly softened.
03 - Add bean sprouts and green onions. Stir-fry for another minute.
04 - Stir in soy sauce, oyster sauce, sesame oil, and white pepper. Cook for 1–2 minutes until vegetables are tender but still crisp. Transfer the filling to a colander and let it cool completely, pressing gently to remove excess moisture.
05 - Place a spring roll wrapper on a clean surface with a corner facing you. Add about 2 tablespoons of filling near the bottom corner. Fold the corner over the filling, then fold in the sides and roll up tightly. Seal the edge with the flour-water paste. Repeat with remaining wrappers and filling.
06 - Heat about 2 inches of vegetable oil in a deep skillet or pot to 350°F. Fry spring rolls in batches for 3–4 minutes, turning occasionally, until golden brown and crisp.
07 - Drain on paper towels. Serve hot with sweet chili sauce or soy sauce.