How to Make It
Preheat the oven to 425°. In a large ovenproof skillet, cook the bacon over moderate heat until browned, about 8 minutes. Spoon 2 tablespoons of the bacon drippings into another large skillet and reserve. Add the onions, thyme and bay leaf to the bacon and cook over moderate heat, stirring occasionally, until the onions are softened and beginning to brown, about 15 minutes.
Carefully add the brandy to the skillet with the bacon and onions and cook, scraping up any browned bits from the bottom, until reduced to 1 tablespoon, about 1 minute. Add 1/2 cup of the chicken broth and simmer over moderate heat until the liquid is level with the onions and slightly thickened, about 2 minutes. Season the onion and bacon sauce with salt and pepper.
Season the chicken breasts with salt and pepper. Heat the reserved bacon drippings until shimmering. Add the chicken breasts skin side down and cook over moderately high heat until the skin is deep golden brown and very crisp, about 8 minutes. Turn the chicken and cook until the bottom is light golden, 3 minutes. Transfer the chicken skin side up to the onion and bacon sauce. Bake in the oven for about 12 minutes, or until the chicken is cooked through.
Meanwhile, add the remaining 1/4 cup of chicken broth to the skillet used for browning the chicken. Simmer over moderately high heat, scraping up any brown bits stuck to the pan, until reduced by half, about 1 minute.
Transfer the chicken breasts to plates. Discard the bay leaf and thyme and stir the reduced broth into the onion and bacon sauce. Spoon the sauce around the chicken and serve.