I first cooked chicken this way following the Cast-Iron Roast Chicken with Lentils and Walnut Vinaigrette recipe from Food & Wine and have since adapted it to my go-to method for cooking chicken. The skin comes out beautifully crispy and if you pay attention and don't burn the love in the pan, it becomes an amazing gravy. We tweak this a bit substituting lemon or adding in ginger, but mostly eat it as is. —savorthis
Remove the chicken's backbone then cut through breastbone. Mix all rub ingredients and rub into chicken. Salt and pepper liberally on both sides. (If I add the rub to the chicken in the morning I usually wait until right before cooking to salt and pepper. )
Preheat oven to 400 degrees and heat a cast-iron pan over medium heat. Once hot, add 2 T of oil and add chicken halves, breast side down. Cover with foil and a heavy weight (I use an enamel casserole) and cook about 10 minutes. Take a peek halfway through to be sure they are not burning. You may also want to rotate the halves so they cook more evenly. Once the skin is a deep golden brown, flip the chicken pieces and place the pan in the oven. Cook, uncovered, for about 30 minutes until the chicken thigh reaches 165. Remove and let rest about 10 minutes.
If there is a lot of rendered fat, you can remove some with a spoon. Whisk in flour and cook a few minutes. Whisk in wine if using and cook another few minutes, then add broth and parsley. Taste and add salt if necessary. (A splash of cream is not a tragedy either).