Heat a large thick based pot to medium hot.
Shell and de-vein the prawns, retain the shells.
Peel and slice the carrot.
Top and tail the celery and slice.
Peel the shallot and garlic and finely slice, keep separate.
Add the oil to the pot gently in a saucepan and add the prawn shells.
Put aside 1 prawn tails per person and add the rest to the shells in the pot.
In a separate pot, warm through the fish stock.
Leave to caramelize without stirring to allow some of the moisture steam away for 2-3 minutes.
Stir thoroughly, and then add the shallots, carrots and celery.Season with half of the salt and pepper
Cook whilst stirring over a high heat for approximately 5 minutes, then add the garlic .
Cook for a further 4-5 minutes until the shallots have become translucent and the smell has no 'bitterness'
Add the cognac and sherry and reduce until dry.
Add the flour and stir thoroughly to prevent sticking to the bottom of the pot.
Add the tomato paste and cook for 2 minutes.
Add the fish stock a little at a time to allow to absorb into the flour.
Bring to the boil, then turn down to a gentle simmer, add the double cream and simmer for approximately 30 minutes.
Remove and place in a cocktail blender or similar and puree until as smooth as possible.
Pass through a sieve back into the sauce pan, adjust the consistency and seasoning with the salt and pepper and water as desired.
Drizzle the remaining prawn tails with the olive oil.
Heat a medium frying pan to high heat and add the prawn tails, turning over when golden and orange on the side in contact with the pan.
Slice the chives and chop the cooked brown shrimp, stir through creme fraiche.
Place 2 of the cooked prawns in each bowl, ladle the finished bisque on top and finish with a dollop of the creme fraiche.
«Try zesting up the soup with a squeeze of lemon, or add a bit of cognac to the the creme fraiche as well.»