From Open Kitchen: Inspired Food For Casual Gatherings by Susan Spungen
1 1/2 tablespoons plus 1 teaspoon salt
2 teaspoons freshly ground black pepper
one 4- to 5-pound chicken
3/4 cup kefir
1/4 cup fresh lemon juice
4 garlic cloves, grated on a microplane
1 tablespoon fresh thyme leaves or 1 teaspoon dried thyme
3 tablespoons harissa, plus more to taste
2 large or 4 small shallots, cut in half with skin on (about 4 ounces)
1 head garlic
3 to 4 sprigs fresh thyme
1 1/2 tablespoons new york shuk-brand rosey harissa or paprika
dried edible rose petals or rose buds (optional)
Combine 1 1/2 tablespoons of the salt and the pepper in a small bowl. Place the chicken in a wide, shallow work bowl and season it inside and out with the mixture. Separate the skin from the breast.
In a separate bowl, combine the kefir, lemon juice, grated garlic, the remaining 1 teaspoon salt, the thyme leaves, and plain harissa. Place the chicken in a 1-gallon resealable plastic bag. Pour the mixture over the chicken and use a rubber spatula to help coat the chicken all over, inside and out, with the mixture. Push some of the marinade under the skin. Squeeze as much of the air out of the bag as possible. Refrigerate for at least 8 hours and up to 24 hours, turning occasionally.
Preheat the over to 400°F.
Scatter the shallots in a small roasting pan or other heavy 9 by 13-inch pan. Remove the chicken from the marinade and let the excess coating drip off, leaving a thin coating, and put it in the pan. Cut off the top third of the garlic head. Put the large part facedown in the pan and the small part in the cavity. Put the lemon half cut-side down in the pan. Sprinkle the thyme sprigs on top. Add 1/4 cup water to the pan.
Roast the chicken for 45 minutes, then reduce the oven temperature to 350°F.
Sprinkle the chicken with the Rosey Harissa and start basting with whatever juices have collected in the pan and in the cavity. Roast, basting every 15 minutes or so and adding 1/4 cup water if the pan looks dry, until the leg feels very loose when jiggled, 1 hour and 30 minutes to 1 hour and 45 minutes. The idea is to let it dry a little so the flavors and juices caramelize but do not burn. Always add 1/4 cup water before it starts to burn.
Transfer the chicken to a carving board to rest. Squeeze the lemon and garlic into the pan juices and mash the shallots with a fork. Strain the juices through a mesh sieve, pressing hard on the solids to extract all the juice. Spoon off some of the grease, if needed. Whisk in extra harissa if you want extra heat.
Pour the jus on a platter. Carve the chicken and arrange it on the platter to soak up the sauce but maintain the crispy skin. Crush the rose petals over the top of the chicken, if using.