Prepare the chicken. Pat the chicken dry. Spatchcock it if not already done, so it sits flat in the sauce. Coat lightly with oil, then season both sides with salt and cracked black pepper, gently pressing the seasoning into the meat.

Par-bake. Preheat the oven to 375°F. Place the chicken in a roasting pan deep enough for the sauce and par-bake for 10–15 minutes while you make the sauce.

Sauté the shallot and garlic. Heat the oil (or bacon grease) in a skillet over medium heat. Add the shallot and cook 1–2 minutes, stirring often, until softened, then add the garlic.

Deglaze. Carefully add the cognac or brandy, scraping up the browned bits. Simmer 1–2 minutes, until reduced by about half. No need to ignite it.

Make the cream sauce. Pour in the chicken broth and simmer 3–4 minutes. Add the heavy cream, Dijon mustard, Worcestershire sauce (if using) and all the seasonings. Cook 4–6 minutes, stirring occasionally, until the sauce lightly coats the back of a spoon. Don’t overcook; most of the cooking happens in the oven. Add the rosemary sprigs to the sauce at the very end.

Bake in the sauce. Remove the chicken from the oven and pour the sauce, rosemary and all, over it. Return it to the oven uncovered for about 50 minutes, basting with the sauce every 15 minutes or so, until the chicken is cooked through (165°F in the thickest part). Don’t skip the basting!

Serve. Garnish with fresh parsley and serve with your favorite sides.