Heat pot then add olive oil.
Add carrots, celery, onion and garlic. Tie thyme and rosemary together and drop into pot with bay leaves.
Season with salt and add peppercorns into pot. Cover and cook veggies until tender-crisp. Turn off heat and let cool.
In a different pot, bring water to a boil, add pearl onions and boil 3 minutes. Drain and cool onions in an ice water bath. Trim at root end and squish the onions away from their skins. Place in fridge.
Add wine and chicken to the pot with the cooled veggies then place pot in fridge and chill overnight.
Remove chicken from wine and pat dry. Strain the wine and reserve it, throw marinated vegetables and herbs. Rinse and dry pot, heat on stove and add olive oil and the bacon. Brown and crisp then remove and reserve.
Season the chicken with salt and pepper, brown in batches until deep golden.
Throw some of the excess fat ...add reserved wine to pot and scrape up any drippings. Add stock and set chicken and bacon back into pot.
Add the chopped carrots and pearl onions. Bring to a boil then reduce heat and cook at a low boil for 20-25 minutes.
Remove chicken, onions and carrots, raise heat and thicken the reddish-brown liquid until it becomes a thin, shiny gravy. Skim the impurities.
In a small skillet, melt butter and whisk in flour (bechamel). Then whisk becahmel into the wine sauce and let thicken.
Serve chicken, carrots and onions topped with plenty of sauce.