Preheat a Le Creuset 5-Quart Round Braiser over medium-high heat. Add 2 tablespoons of olive oil and 2 tablespoons butter to the pan. Season the chicken liberally with salt and pepper and when the pan is hot, add the chicken, skin side down, and brown the chicken until golden, about 5 minutes per side. Remove and reserve.

Add the bacon to the pan along with the remaining 2 tablespoons of butter. Then add the onions and cook the mixture over medium heat, stirring often, for about 20 minutes or until the onions and bacon pieces are caramelized and golden. During the last 5 minutes, add the apple slices to the sauté. Add the vinegar and scrape up any bits from the bottom of the pan. Add the thyme sprigs, fennel seed, red pepper flakes, maple syrup, apple cider and chicken stock and bring the mixture to a simmer.

Return the chicken to the pot with the liquid and onions, cover the pot with a lid or aluminum foil, and simmer over medium heat for about 20 minutes or until the chicken is cooked through. Baste the chicken with the sauce about halfway through the cooking process. Once cooked through, remove the chicken to a plate and keep warm. Raise the heat to high and simmer the sauce for 5 minutes or until it thickens enough to coat the back of a spoon.