Season the chicken with salt and pepper and add to a deep bowl.
Add the bouquet garni to the bowl with the chicken and pour in the red wine. The wine should completely cover the chicken. Cover and marinate overnight.
Add the chopped bacon to a large Dutch oven, while bringing the heat up slowly to render out the fat. Cook for approx. 15 minutes until the bacon is nice and crispy.
Using a slotted spoon, remove the bacon and transfer to a paper towel. Leave the excess fat in the pot.
Remove the chicken from the marinade and thoroughly dry the chicken with paper towel. NOTE: Don't discard the wine.
With the remaining bacon fat, increase to high heat and place chicken in the hot skillet until nicely browned. About 3-4 minutes per side. Remove the chicken from the pot and set aside. NOTE: Work in batches. Be careful not to over crowd the pot, otherwise you won't get a nice sear on the chicken.
Lower the pot to medium-high heat. Add 200g of the sliced mushrooms, 100g diced white onion, minced garlic cloves, and 100g of the diced carrots (optional) to the pot and cook until the vegetables are softened. About 10 minutes.
Stir in tomato paste and cook for about 3 minutes.
Pour brandy into the pot and deglaze the pan by scraping up the brown bits to reincorporate them into the sauce. Cook until liquid has evaporated, approx. 2 minutes.
Add the wine, including the bouquet garni back into the pot. Stir to incorporate and bring the wine to a boil. Cook until wine has reduced by half, approx. 15 minutes.
Sprinkle the thickener to the pot (xanthan gum or konjac flour) and stir to combine. Start with1/8 tsp and work your way up as needed. You shouldn't need anymore than 1/2 tsp. If needed , slowly add more thickener throughout the cooking process. Being careful not to add too much to the stew.
Add the chicken and half the bacon back to the pot and reduce the heat to low. Simmer for 1 hour until the chicken has cooked and the sauce has thickened.
While the stew is simmering, heat olive oil and butter in a large nonstick pan. Add the pearl onions and sweetener. Cover and reduce the heat to low. Cook for 15 minutes, shaking the skillet often to move the onions.
Add 200g of the quartered mushrooms to the pan with the pearl onions. Cook for approx. 7 minutes until softened.
Once the stew has simmered for an hour, add the quartered mushrooms and pearl onions to the Coq Au Vin. Sprinkle on fresh parsley and remaining cooked bacon.
Serve with a simple salad or cauliflower mash. Enjoy!