Put the chicken in salted water and once it comes to a boil, add the cut in half onion head, halved garlic cloves and peppercorns. Allow to boil for about 30 minutes.
Preheat oil in another container and put the cleaned and sliced mushrooms in to fry. Once tender and braised, add the flour and stir vigorously. Once dissolved, remove it from the heat and gradually add 2 1/2 cups (600 ml) of the broth.
Return to the heat and stir it for about 5 minutes until you get a thick fricassee sauce. Chop the dill and add it to the dish.
Finally, mix in the chicken and pour the cream in a trickle. Stir, and if necessary season with pepper and salt.