Start by freeing the tails and use the rest of the langoustine to make the stock for the risotto, as you can see the recipe here.

Start by rolling out cling film on the kitchen counter and drizzle a bit of truffle oil on it. Place the tails on the oil on top of each other and add a bit of salt and white pepper. Drizzle some more oil on top and wrap them up like a sausage in the cling film. Tighten the film around and prick a few holes in the film. Wrap the whole thing in a new piece of cling film, tightly sealing both ends with either a clip or string.

Cook the tails in sous vide/water bath for 25 minutes at 49 degrees Celsius (120 degrees Fahrenheit).

Take the fish out and pat it dry. Roll it in leek ash (see the recipe here) and slice it into thin slices.

We didn't manage to get the tails to stay together, so they fell apart when sliced. Next time, we will use meat glue to keep them together.

Sauté the onions and rice in butter and oil over medium-high heat in a heavy-bottomed pan. Add the white wine and let it reduce. Add salt and pepper.

Next, the stock should be added slowly over 20 minutes. Then add the cream and grated Parmesan to the pan and give it another 5 minutes.

Taste and adjust with salt, pepper, lemon juice, and vinegar.

Serve the dish with a fresh salad and freshly ground pepper and grated Parmesan on top.