Season the chicken pieces well. Peel the pearl onions. In a small pan boil some water and add the bacon. Blanch for 3 to 4 minutes and drain.
In a casserole melt the ¼ cup butter and 1 tablespoon oil. Add the bacon and the onions and fry until golden. Remove and drain thoroughly. Brown the pieces of chicken in the fat in the casserole, turning them over several times.
Return the bacon and onions to the casserole. Heat 1 tablespoon Cognac, pour into the casserole and ignite. Pour the whole (750ml) of red wine, 1 bouquet Garni and 2 crushed garlic gloves. Bring slowly to the boil, cover and simmer for 1 hour.
Thinly slice the mushrooms. Fry them in the 2 tablespoons butter and add to the casserole. Continue cooking for another 20-25 minutes.
A few minutes before serving, cream the ¼ cup butter with the flour. Gradually stir in a little cooking liquid from the casserole, and then pour this mixture slowly into the casserole. Cook stirring for 5 minutes
Served with steamed potatoes or fresh pasta.