For the dressing, sauté the prawn heads in the oil.
Add the celery, shallots and tomato purée.
Sear it for a little while, add the poultry stock, and leave to simmer for about 20 minutes.
Subsequently, pass the mixture through a fine sieve.
Season the soup with salt and pepper and leave to cool.
Add the egg yolks and the sushi vinegar, and use grape-seed oil to thicken the dressing.