1. Place shitake mushrooms in a small bowl, cover with boiling water and soak for 20 minutes. Drain and squeeze out excess water. Remove stalks and chop into fine dice.
2. Place pork mince in a large bowl, add diced shitake, ginger, spring onions, coriander, soy sauce, egg and black pepper. Using your hands, combine well.
3. Lay out a few wrappers at a time on a clean bench. Place a small spoonful of pork mixture in the middle of each wrapper. Use a pastry brush or finger to wet the edge of the wrapper with water. Fold over into a crescent shape and seal by pressing your fingers together along the edge. Place dumplings on a lined tray, making sure the edges don’t touch. When all the dumplings are made, place in the refrigerator until ready to cook.
4. Whisk together ingredients for dipping sauce. When ready to cook, fill steamer with water and bring to the boil. Spray the base of steamer with oil to prevent sticking or line steamer with a piece of baking paper. Steam dumplings in batches (without overlapping edges) for about 5 minutes each batch. Remove dumplings and allow to cool slightly before serving with dipping sauce. Garnish with picked coriander leaves.