How to Make It
Preheat the oven to 450 degrees. Using a sharp knife, remove the chicken breast from the bone and split into two breast halves. Separate the legs from the chicken. Starting at the thigh end of the leg, begin scraping the meat away from the bone in a firm pushing motion. Continue this process until you are one 1/2-inch from the end of the bone. It will look like an inside-out chicken leg with a little knuckle just above it. Use your knife to separate the leg from the bone. Turn the meat back inside itself, much like turning an inside-out sock right-side-in. The chicken should be separated into 4 pieces.
In a large oven-safe sauté pan, heat 4 tablespoons of oil. Season the chicken on all sides with salt and pepper and cook skin side down over moderately high heat until the skin is crisp and golden brown, about 5 minutes. Transfer the pan to the oven and cook until the juices run clear and an instant-read thermometer inserted into the thickest part reads 160°, 20 to 25 minutes.
Meanwhile, in a large skillet, heat 4 more tablespoons of oil. Add the torn bread and toast over moderately high heat, turning occasionally, until lightly browned on all sides, about 3 minutes. Add 4 tablespoons of the butter, 1 sprig of thyme, 1 sprig of sage, the rosemary, 2 of the garlic cloves and the shallot and cook until the bread is golden brown and the shallot is tender, about 5 minutes more. Transfer the croutons to a platter.
Remove the chicken from the oven and plate skin side up on top of the croutons. Degrease the leftover juices in the pan and then bring to a boil over moderately high heat. Add the stock and scrape up any bits on the bottom of the pan. Add the remaining 3 sprigs of thyme, 2 garlic cloves and the remaining 8 tablespoons of butter. Cook until the sauce is thick and glossy, about 10 minutes. Season with salt and pepper and pour over the roasted chicken; serve.