Cook the veal neck in the Big Green Egg for 10 to 15 minutes, allow to cool, vacuum-seal it in a sous-vide bag and then cook it for 48 hours at 61°C (141°F). Bring the temperature back down quickly and retain the cooking juices from inside the bag. Soften the onions, then add the wine and the herbs and spices and reduce to a quarter of the liquid. Add the stock and reduce to 300 ml. Pass through a sieve then through a cloth, return to a pan and thicken with a beurre manié (dough of butter and flour). Simmer for a couple of minutes, stirring all the time.
Mix the cream with the egg yolk, whisk it into the reduction, then mix in the crème fraîche and season with salt, pepper and lemon juice. Reduce the carrot juice, honey and ginger, then use it to glaze the warm carrots and season to taste with a little salt. Remove the outer layers of two leeks and slice the white part into sticks of 4 to 5 cm (1.5 - 1.9 inch). Vacuum-seal it in a sous-vide bag together with a little olive oil and salt and cook for 30 minutes at 85°C (185°F).
Peel 20 pickled onions and vacuum-seal them in a sous-vide bag together with a little olive oil and salt. Microwave for 1 minute at maximum power, allow to cool and then cut open the bag. Finely julienne slice the celeriac and deep-fry at 140°C (284°F) until crisp. Drain and then sprinkle with a little finely ground salt. Cut the veal neck into nice rectangular slices and fry them briefly in butter.