Remove the guinea fowl capon supremes and thighs. Cut the supremes into two pieces and separate the drumsticks from the thighs. Cut up the rest of the carcass. Peel and clean the button mushrooms. Cut them into 2 or 4 depending on their size. Cut the ventrèche into small lardons.
Pour 30 grams of duck fat into a large cast-iron casserole dish. Season all the pieces of meat with salt. Fry until nicely colored on all sides, then remove to a shallow dish. In the same cooking fat, sauté the button mushrooms and bacon until nicely colored. Remove from the pan.
Pour the capon carcasses into the casserole dish and season with salt and Espelette pepper. Add a little fat if necessary.
Once the bones have browned, add the herbs and garlic cloves. Deglaze with the vin jaune, detach all the juices and reduce by half. Pour in the chicken jus, simmer for ten minutes or so, then add the cream. Simmer on a low heat for a further twenty minutes. Strain to remove only the sauce. Season with salt and Espelette pepper.
Place the capon pieces in the casserole, along with the mushrooms and bacon. Pour in the cream sauce and place in a pre-heated oven at 170°C. Leave to simmer for around twenty minutes. Serve straight from the pot.
Depending on the season, the button mushrooms may be replaced by morels, ceps, chanterelles or other wild mushrooms.
Bon appétit !