Preheat oven to 180 gr.S.
Peel onion, chop coarsely and place in pan.
Add to the onions olive oil and cook over medium heat, stirring often, until the onion becomes golden and transparent.
Mushrooms wash, dry with paper towels and cut.
Add them to the pan with the onion, stir and continue to cook for about 10 minutes, or until all the liquid has evaporated.
If necessary, add a little more olive oil. Season with salt and pepper mushrooms and onions. At the end of the frying pan, add the boiled and diced chicken, stir and turn off the heat.
In another frying pan or a small pan fry lightly (to cream color) over medium heat a tablespoon with a hill of white flour.
Add two tablespoons of butter andstir until the butter has melted. Then slowly add the cream in a saucepan (or sour cream) and cook over low heat, stirring constantly, until the sauce thickens.
Fill the tartlets or ceramic pots with a mixture of chicken with mushrooms and onions.
Drizzle each serving with white sauce and sprinkle with grated cheese.
Expose all the tartlets (pots) on a baking sheet and return to oven.
Bake for about 12-13 minutes, until the top of each portion is formed rosy cheese crust.
Serve julienne Chicken with mushrooms hot, with fresh baked bread.