1. Put each crab on the counter with its back facing down; Insert a knife through its abdomen and hold it till the crab has stopped moving; Remove the reeds/strings; Separate the carapace from its body by lifting it; Discard the gills, the guts and the gizzard in the lower center part of carapace; Scrub the crab with a small brush to discard the dirt; Rinse and drain; Cut each half into 3 pieces; Cut pincer into halves; Keep the carapace in whole; Wipe dry; Slightly coat with potato starch.
2. Rinse and slice ginger; Rinse and cut spring onion into sections; Peel, rinse and mince garlic.
3. Add seasoning (2) to a bowl and mix well.
4. Add 800ml oil to a wok; Bring to the boil over a high heat; Jiggle the crab in the oil for 1 minute; Remove and drain.
5. Set the oil aside, leaving 1t oil; Heat the wok over a high heat; Stir-fry ginger, spring onion and garlic over a medium till fragrant; Return the crab to the wok; Add 2t Shaoxing wine and stir-fry over a high heat briefly; Add 1 cup of water and seasoning (1); Stir-fry over a high heat till mixed; Cover with a lid; Cook over a high heat till the sauce has dried up; Add seasoning (2) and stir-fry over a high heat till the sauce has thickened. Ready to serve.
After separating the carapace from the crab's body, it is important to discard the gills, guts and the gizzard completely, and scrub the crab thoroughly with a small brush, so that the mud and dirt would not get into the sauce, affecting the taste and even the health.