Place the prawns on a plate and top with the ginger. Place in the steamer and steam until the prawns are cooked, about 4-5 minutes. Remove from the steamer and set aside.
For the sauce, mix chillies, garlic, coriander root, pickled garlic, lime juice, fish sauce and palm sugar. Give the sauce a taste. There should be a good balance between salty, sweet, spicy and sour. Adjust if necessary.
Slice the bitter gourd and boil in salted water until very soft. Place the gourd slices on a plate. Place the prawns and ginger on top of the gourd. Pour the sauce over the prawns.
To serve, garnish the prawns with chopped coriander and enjoy!