Rinse the chicken, cut into pieces and put in a simmer for 4 hours. Water should cover the nest for 2 cm. One hour before the end of cooking, add bay leaf, onions, carrots, parsley root, salt and pepper to taste in a pan.
Remove the meat from the broth, separate the meat from the bones and cut into pieces.
Boil the mushrooms and chop finely.
Strain the broth and dissolve the gelatin in it.
Arrange the meat and mushrooms on a plate and fill with broth. Put in a cool place until completely solidified.