Season the chicken with salt, pepper and a little cayenne pepper if you want a little spice.
Slice the mushrooms thickly and the carrots into horizontal 2 inch rounds. Dice the celery. Dice the shallots and onions and set everything aside into separate bowls.
Heat your cast iron pot on medium high for about 5 minutes and then add the olive oil. Add the chicken pieces skin side down into the pan – careful not to overcrowd the pot. Cook in batches if your pot is not big enough to cook all at once.
Fry the chicken for 3-5 minutes each side until browned and crisp. Once done remove from the pan and set aside on a plate to collect the juices.
Now scrape any really burnt bits from the pot and add a little oil if needed before adding the pancetta or lardons to fry. Fry these until the fat has almost completely rendered and then turn off the heat and remove to the same plate as the chicken.
Place the pot back on the heat and fry the onions, shallots and garlic in the pancetta fat left behind. Fry for 2-3 minutes or until fragrant and translucent. Add the garlic a minute or 2 after the onions as garlic cooks a lot faster and you don't want it to burn.
Turn the heat to medium and add the sliced carrots, celery and mushrooms to the pan and sauté for about 5 minutes. Then add the flour and stir to cook for about 3 minutes.
Add the cognac or brandy to deglaze your pan. Use a wooden spoon to remove all that stuck on flavour from the bottom of your pot. This process should take about 3-5 minutes.
Next pour in the wine, stock, seasonings and bouquet garni and stir. Add the pancetta and mix everything before placing the chicken pieces back into the pot using tongs. Be sure to pour all the juices that remain in the dish. Cover the pot and leave on high to come to the boil.
After about 5-7 minutes your stew should be boiling. Lift the lid stir a little and turn the heat down to low. Set a timer for 1 hour and leave to cook with the lid on.
After one hour check your stew it should be coming along nicely and starting to thicken up and change colour. Recover and leave to cook for a further 30 minutes - this will depend on your pot and the type of chicken you used.
After 15-30 minutes check your chicken and try the sauce. If the chicken is tender and the sauce has thickened and tastes amazing then its ready.