Pat chicken pieces with paper towels until dry, then season chicken with salt and pepper & set aside
In a large Dutch oven, cook bacon over medium-low heat until fat has rendered and the bacon is golden and crisp, 10 to 15 minutes.
Using a slotted spoon, transfer to a paper-towel-lined plate, leaving rendered fat in the pot.
Heat bacon fat over medium heat until it’s just about to smoke.
Brown chicken on all sides in the hot fat.
Cover the pan, and cook slowly (300 degrees) for 10 minutes, turning the chicken once.
Heat oil & butter in a frying pan, add onions, and toss for several minutes until lightly browned.
Add water to halfway up the onions and ¼ to ½ teaspoon salt, cover the pan, and simmer for 20 minutes, or until the onions are tender when pierced with a knife.
Then uncover the chicken, pour in cognac, and ignite with a flame.
Shake the pan back and forth until the flames subside.
Pour wine into the pan, and add enough bouillon to cover the chicken.
Return bacon to the pan,
Stir in tomato paste, garlic, bay leaf, and thyme.
Bring to a simmer, then cover and simmer for about 20 minutes, or until the chicken meat is tender when pierced with a fork.
Heat butter & oil in a frying pan; when hot, toss in mushrooms and sauté over high heat for 4 or 5 minutes until lightly browned.
When the chicken is done, drain out the cooking liquid into a saucepan. Skim off fat and boil down liquid, if necessary, to concentrate flavor.
You should have about 2¼ cups. Remove from heat.
Blend 3 tbsp butter and 3 tbsp flour in a saucer;
Whisk butter/flour mix into the cooking liquid with a wire whip.
Bring to a simmer, stirring, and simmer for a minute or two until the sauce has thickened.
Scrape onions and mushrooms into the sauce and simmer for a minute to blend flavors.
Carefully taste the sauce, adding more salt and pepper if needed
Then pour the sauce over the chicken.
Before serving, bring to a simmer, and baste the chicken with the sauce. Cover and simmer for 4 to 5 minutes, until chicken is hot through.
Serve from a casserole, or arrange on a hot platter and decorate with sprigs of parsley.