Shell the prawns.
Soak the sheets of gelatine in cold water.
Finely dice the carrot and cook it.
Chop the fresh herbs.
Heat the mussel jus and melt the gelatine in it.
Add the cooked diced carrot and the fresh herbs. Leave to cool.
Peel the avocado and chop into a mirepoix.
Take a presentation ring and place a layer of the prawns and avocado in it.
Cover with the warm gelatine preparation.
Place in the refrigerator.
Hollow out the cherry tomatoes and stuff them with the remaining aspic jelly.
Remove the stalks from a few of the watercress leaves and set aside for decoration.
Blanch the remaining leaves, and then chill them in iced water.
Blend the blanched water cress with the cream in a food processor until the consistency is smooth and velvety.
Present the dish on a soup plate: the prawns in aspic, the stuffed cherry tomatoes and the cream arranged around the aspic.