Peel and finely dice the shallots. Peel the Jerusalem artichokes and cut into cubes.
Heat a large saucepan and then sweat the shallots with the butter. Add the artichoke, cover and cook for 10 minutes. Add water to half the height of the artichoke, bring to the boil and simmer for 20 minutes. Remove from the heat and blend until smooth. Add the cream and check the seasoning.
Peel the prawns and use the tip of a sharp knife to remove the black spine.
Heat a frying pan to hot, add a drizzle of olive oil and cook the prawns for 1 minute then turn over and remove from the heat. Leave the prawns in the pan for 2 more minutes to finish cooking.
Pour the artichoke veloute into soup bowls. Place the prawns on top and finish with a little freshly ground pepper and a pinch of fleur de sel.
«To stop the Jerusalem artichokes from discolouring once peeled, place them in a bowl of water with half a lemon.»