1. Prepare the chicken
Put 1.5 liters of water in a pan on the fire and bring to a boil. Wash the chicken fillet with cold water and put in boiling water. Lower the fire and cook for 30 minutes. Transfer the finished fillet to a bowl of very cold water to cool.
Instead of breast you can use chicken thighs. They cook the same way. Remove the skin from the finished thighs, or it will ruin the julienne.
Cut the cool chicken into small pieces, then disassemble into fibers and put in a separate bowl.
2. Prepare onions, cheese and mushrooms
Peel the onion from the skin. Cut in half and chop into thin half rings or small cubes. Place the chopped onion in a separate bowl.
Put the mushrooms in a bowl of sufficient size, pour in cold water and sprinkle a spoonful of flour on top. Carefully, without removing the water, rinse the mushrooms. Flour acts as a mild abrasive: it removes dirt without damaging the delicate structure of the mushrooms. When the powdery water turns grey, drain it and rinse the mushrooms under the tap.
Cut the mushrooms into the thinnest possible slices. Large hats pre-cut in half. Place chopped mushrooms in a separate bowl.
Finely grate the cheese. Instead of cheddar, you can use any hard cheese that melts well: Maasdam, Russian, Dutch, Gouda, and even Parmesan. It is better to take quite a bit of the last cheese (a pinch for each serving of julienne), otherwise it will drown the taste of the dish.
3. Saute mushrooms and onions
Place a heavy pan over medium heat. When the dishes are hot, pour in all the sunflower oil.
Put the onion in the hot oil. Let it go until transparent and add the mushrooms. Add fire and fry until moisture disappears. Remove the cooked mushrooms with onions from the pan.
4. Combine the ingredients
Place the pan over medium heat. Melt half of the butter. Pour in the cream. Instead you can use 15% sugar or even milk. When the cream starts to boil, add the shredded chicken and stir.
Heat the fillet pieces for a minute, and then add the mushrooms with onions and the remaining tablespoon of flour. Continue cooking, stirring vigorously, until the cream thickens. Season with salt and pepper at the end.
5. Bake the julienne
Turn on the oven at 150 °C. While it is heating, form the julienne. Use portioned cocotte makers (small metal pans with handles). If there are no cocotte makers, you can use disposable foil cupcake liners, ceramic pots, or small buns.
Divide the hot chicken-mushroom mixture among the cocotte makers, counting so there is one serving for each diner. It is important that the julienne does not reach the edge of the cocotte by at least 7 mm.
Sprinkle each serving with grated cheese. Put a small piece of butter on top. Transfer the filled coquettes to a baking sheet and put in the oven for 10 minutes. Use the top heat.
Once the cheese is brown, remove the julienne and serve immediately. To prevent the dishes from cracking when hot, place a paper napkin under the coquette maker on a plate. If the appetizer is not served immediately, leave it in the turned off hot oven. To prevent the julienne from drying out, pour a glass of boiling water on the baking sheet and close the door tightly.
Do not try to make julienne for the future, because when it is cooled, it loses its taste. If the chicken with mushrooms remains, send the food to the refrigerator: make fresh julienne the next day. In the refrigerator, the workpiece will last up to five days.