Step 1: Heat a tablespoon of oil in a large wok or skillet over medium-high heat. Add the ground pork and cook until browned, breaking it into small crumbles.
Step 2: Add the minced garlic and ginger to the pork and sauté for 1 minute until fragrant.
Step 3: Toss in the shredded cabbage, carrots, and shiitake mushrooms. Stir-fry for 3-4 minutes until the vegetables have softened slightly but still retain some structure.
Step 4: Stir in the soy sauce, oyster sauce, sesame oil, and white pepper. Mix well to ensure the filling is evenly seasoned.
Step 5: Transfer the filling to a colander or a large baking sheet. Allow it to cool completely and drain any excess liquid. This is vital for a crispy spring roll recipe.
Step 6: Place one spring roll wrapper on a flat surface in a diamond orientation. Place 2 tablespoons of filling on the bottom third of the wrapper.
Step 7: Lift the bottom corner over the filling and tuck it under. Fold the left and right corners toward the center. Roll upward tightly.
Step 8: Dab a small amount of the cornstarch slurry onto the top corner to seal the roll completely.
Step 9: Heat 2-3 inches of oil in a heavy-bottomed pot to 350°F (175°C).
Step 10: Fry the rolls in batches for 3-5 minutes, turning occasionally, until they are golden brown and crispy. Drain on a wire rack or paper towels.