Start by cooking the vegetables in a vacuum-sealed bag at 83°C for 30 minutes. Remove and cool in ice water. Then proceed to juice the root vegetables with the help of a juicer or an extractor. Whisk in the hazelnut oil and vinegar.
Next, move on to cooking the guinea hen. To cook guinea hen, it must be cleaned and prepared. Once cleaned and prepared, bake the whole guinea hen in the oven at 180°C for about 30 minutes. Remove from the oven and let rest. Let cool until the guinea hen is just slightly warm. Next, separate the guinea fowl into parts and place the pickled grape leaves on top of the breast. Place the guinea fowl on a plate and sprinkle the root sauce over it. To conclude, finish with the pan drippings (au jus). Serve and enjoy.