Andrew Wong's Har Gao Prawn Dumplings

Name: Andrew Wong's Har Gao Prawn Dumplings
Prep time: 2 h
Total time: 2 h
Cuisine: Asian, Chinese
Ingredients: 250g peeled raw prawns; 20g white vegetable fat; 15g sugar; 5g potato starch; 1 teaspoon sesame oil; 5g fine salt; Pinch of white pepper; 75ml ginger and spring onion water (made by crushing fresh ginger and spring onion trimmings and infusing in water for 30 minutes); 110g wheat starch; 110g tapioca flour; 70g potato starch; Approximately 200ml boiling water; 50ml vegetable oil; Stand mixer fitted with dough hook; Bamboo steamer or steamer basket; Rolling pin; Dumpling scraper; Small saucepan; Stick blender; Digital thermometer (recommended)