Put the supremes in a vacuum bag with truffle oil, cream (120 g per bag), salt and pepper. Bake at 63°C (145°F) for 1 hour. Cool immediately in ice.
Clean the ceps and chanterelles and cut the ceps in 4 pieces. Sauté the mushrooms separately in a frying pan with the oil. Add the butter and the chopped flat-leaf parsley. Season. Spread the Emmental on a Tefal plate and place under the salamander grill until it becomes blond.
At the time of service, heat the chicken supremes in the bain-marie. Open the bag, collect the sauce. Reduce to a coating consistency. Cut the chicken. Dress with all the ingredients.