Heat the oven to 425 degrees. Remove the chicken giblets. Rinse the chicken inside and out. Remove any excess fat and leftover pinfeathers and pat the outside dry. Place the chicken in a roasting pan just large enough to hold it.

Liberally salt and pepper the inside of the chicken. Stuff the cavity with the bunch of thyme, both lemon halves and all the garlic. Brush the outside of the chicken with the butter and sprinkle again with salt and pepper.

Tie the legs together with kitchen string and tuck the wing tips under the body of the chicken. Scatter the onion slices around the chicken. (See Tip for cooking instructions if you'd like to also roast potatoes and carrots with the chicken.)

Roast the chicken for 1 1/2 hours, or until the juices run clear when you cut between a leg and thigh. Remove to a platter and cover with aluminum foil while you prepare the gravy.

Preheat the oven to 425°F (220°C) — 10 minutes

Pat the chicken dry with paper towels — 2 minutes

Rub the chicken with olive oil, salt, pepper, thyme, and rosemary — 3 minutes

Stuff the cavity of the chicken with halved lemon, minced garlic, and quartered onion — 5 minutes

Place the chicken breast-side up in a roasting pan and arrange lemon slices around it — 2 minutes

Roast in the preheated oven for about 1 hour and 15 minutes, or until the internal temperature reaches 165°F (75°C) — 75 minutes

Bring broth to a simmer and pour over couscous.

Remove all the fat from the bottom of the roasting pan, reserving 2 tablespoons in a small cup. Add the chicken stock to the pan and cook on high heat for about 5 minutes, until reduced, scraping the bottom of the pan.

Let the chicken rest for 10 minutes before carving — 10 minutes

Cover and let sit for 5 minutes, then fluff with a fork.

Combine the 2 tablespoons of chicken fat with the flour and add to the pan. Boil for a few minutes to cook the flour. Strain the gravy into a small saucepan and season it to taste. Keep it warm over a very low flame while you carve the chicken.

Stir in lemon zest, lemon juice, olive oil, and parsley.

Slice the chicken onto a platter and serve immediately with the warm gravy.

Season with salt and pepper.

Garnish with fresh thyme sprigs and serve — 2 minutes