In a small bowl, mix together the harissa with 1/4 cup olive oil and 1 teaspoon salt. Place the chicken in a baking dish or a large, shallow bowl-something that it can rest flat in. Use your fingers to gently make space between the chicken skin and the meat(including the legs). Rub half the harissa mixture underneath the skin on the entire bird. Do your best not to tear the skin (though if it happens, it's not the end of the world). Rub the rest of the paste all over both sides of the chicken. Be careful not to touch your face or eyes with the harissa in your hands.

Cover the dish with plastic wrap and set the chicken in the fridge for a few hours, preferably overnight--and if you're really planning ahead, as long as 2 days.

When you're ready to cook, take the chicken out of the fridge and let it come to room temperature. Meanwhile, preheat the oven to 500°F and park one cast-iron pan (the smaller one if you have different sizes) in the oven to get hot. Set the larger pan over high