Heat 1 tablespoon of the butter in a thick bottomed casserole (with a lid) on the stove top. Sauté the onion and mushrooms for a minute or two. Grate in the garlic and add the chopped bacon. Continue to sauté for three to four minutes. Stir in the balsamic vinegar and cook for a moment or two. Remove the onion, mushrooms and bacon from the pan and set aside to keep warm.
Add the remaining butter to the pan and sauté the chicken breasts on both sides until they are just beginning to turn golden brown. Return the onion, mushrooms and bacon to the pan.
Pour over the brandy. At this point, you can carefully ignite the brandy with a match and allow it to flame for a moment or two before popping the lid on to extinguish it. However if there are kids running around or working with open flame feels a bit too stressful for a weeknight, it’s totally okay just to cook this for a few moments at high heat allowing the brandy to permeate the other ingredients while reducing at the same time.
Add the chicken stock and the red wine, along with the Herbs de Provence, salt, pepper and nutmeg. Lower the heat, clamp on the lid and allow to simmer together for about fifteen to twenty minutes or until the chicken reaches an internal temperature of 165°F and no pink remains inside.
Remove the chicken from the pan and keep warm. Blend the corn flour with the water and add to the sauce in the pan. Stir to mix thoroughly and cook for a couple of minutes until the sauce thickens up nicely. Taste for seasoning and adjust with a bit more salt and pepper if necessary. Stir through 1 teaspoon of the dried flat leaf parsley.
Serve the sauce over the chicken breasts garnished with the remaining flat leaf parsley.