Start to finish: 2 hours 15 minutes
2 whole chickens (4 to 5 pounds each), giblets discarded
2 tablespoons extra-virgin olive oil
Kosher salt, to taste
Ground black pepper, to taste
4 teaspoons dried thyme, divided
1 large yellow onion, quartered
¾ cup dry white wine
¾ cup water
4 tablespoons butter or margarine
½ cup honey
1 ½ cups apple cider, divided
2 tablespoons lemon juice, divided
2 cups chicken broth
3 tablespoons all-purpose flour
Heat the oven to 425 F and set the oven rack is in the middle of the oven.
Pat the chickens dry with paper towels and rub 1 tablespoon of the oil over the outside of each. Sprinkle the inside and outside of the chickens with salt, pepper and 1 teaspoon each of the thyme. Stuff each chicken with 2 onion quarters. Tuck the wings behind the back and tie the legs together with kitchen twine.
Arrange the chickens, breast side down, on a V-rack set inside a roasting pan. Roast until the chickens are golden, about 45 minutes. Remove the roasting pan from the oven and carefully, using paper towels, flip the chickens so that they are breast side up.
Raise the oven temperature to 450 F. Pour the wine and water into the roasting pan. Return the roasting pan to the oven and roast until the thigh meat registers 165 to 170 degrees, about 1 hour. If the pan dries out, add more water ½ cup at a time.
Meanwhile, to make the glaze, in a small saucepan over medium heat, combine the butter and remaining 2 teaspoons of thyme. Melt the butter and cook, stirring occasionally, for 5 minutes. Add the honey and ½ cup of the apple cider, then simmer until the glaze has thickened and reduced a bit, about 10 minutes. Stir in 1 tablespoon of the lemon juice and set aside.
Remove the roasting pan from the oven and brush the chickens evenly with a thick layer of the glaze (you'll have some remaining to brush on later) and continue to roast until the glaze is golden brown, about 10 minutes. Transfer the chickens to a cutting board, brush with the remaining glaze and let rest for 15 minutes before cutting (do not clean the roasting pan).
To make the cider gravy, whisk ½ cup of the chicken broth and flour in a small bowl until smooth. Set aside.
Set the roasting pan over 2 burners on medium-high heat. Add the remaining cider and bring to a boil. Cook, scraping up the browned bits from the pan, until the liquid is reduced by about half, about 5 minutes. Add the remaining 1½ cups of broth. Increase the heat to high and return to a boil, whisking often. Boil until the liquid is reduced by about half, 5 to 7 minutes.
Whisk the reserved flour-broth mixture into the pan. Boil, whisking constantly, until the gravy is thickened, 1 to 3 minutes. Remove from the heat and pour the gravy through a fine sieve into a large measuring cup (discard the solids). Stir in the remaining 1 tablespoon lemon juice and season with salt and pepper, to taste.
Serve the chicken with cider gravy for passing.