Place a crab on a cutting board, cut it quickly all the way through lengthwise with a heavy knife. Do the same with all the crabs.
Cut the apple and the vegetables into pieces. Sauté the crabs for a minute in the oil, add the vegetables and allow them to gain a little color. Add the tomatoes, apple, herb stems and spices.
Sauté a little more. Add the cider and water until they cover the ingredients. Bring the liquid to a boil and skim it. Boil for 45 minutes, if necessary run the shells through a food processor, return them to the bisque and bring back to a boil. Drain the bisque, preferably through a colander with large enough holes so you can press some of the crab mixture through. Boil the liquid again until you have a suitable intensity and consistence.
You now have lots of choices. Here are five:
Thoroughly boil the bisque with tomatoes and garlic. Add to taste – salt, pepper, lemon juice and if you like, some sugar. Serve with aioli.
Thoroughly boil the bisque with whipping cream. Add to taste – salt, pepper, lemon juice or apple cider vinegar.
Thoroughly boil the bisque with lemon grass, chili, lime leaves and more ginger. Add to taste – lime juice, cane sugar and fresh coriander.
Like 3, but add coconut milk before flavoring to taste with the lime juice etc.
Use the bisque in risotto and as a basis for cream sauce to go with white steamed fish.