For the pot au feu with vegetable strips and Jerusalem artichoke chips, remove the crayfish tails from their shells and set aside.
For the crayfish broth, chop greens. Peel onion and cut into wedges. Fry crawfish carcasses in 3 tablespoons hot oil. Add greens and onions and sauté. Deglaze with wine and boil a little. Add a liter of water, bring to a boil and remove the foam.
Add spices and simmer on low heat in an open saucepan for about 1 hour.
Then empty the stock through a dish towel into a saucepan and squeeze out the carcasses. Reduce the stock by half and degrease. Peel and chop the shallot and garlic clove. Heat the remaining olive oil in a saucepan. Sauté shallot and garlic in it and deglaze with 500 ml crayfish stock. Reduce again.
In the meantime, cut zucchini, peeled carrot and peeled celery into narrow strips. Peel Jerusalem artichoke and cut into narrow slices. Heat oil in a saucepan, fry Jerusalem artichoke slices until golden brown and drain on paper towels. Season with salt.
Steam vegetable strips in hot crayfish stock until soft. Add crayfish meat and heat. Remove vegetable strips and crawfish meat from broth and place in plates.
Gradually add cold butter in flakes to crawfish broth and whisk to combine. Season with salt and pepper