Head Notes: The all-purpose spice mix varies between households in the Middle East and Turkey. The version included is my own, amped up with extra spice, smoked paprika and an extra helping of freshly toasted cumin. I keep a bottle of this magical blend on hand at all times. I can't resist adding it to marinades for grilled lamb and vegetables (please don't miss an opportunity to sprinkle it on some eggplant or cauliflower before roasting). It is my savior on those busy nights when I need to boost the flavor of a quick meal. Soon, I'll turn to simply dipping my olive oil soaked bread in a shallow bowl of the stuff. It's positively addictive.
For the spiced butter: Combine the butter with 1/4 cup of the spice blend in a medium bowl. Beat with a wooden spoon until well combined. Simple, but oh so special.
For the chicken: To spatchcock a chicken, cut along each side of the backbone with sharp scissors or poultry shears. Remove the backbone, and reserve it for stock; I collect poultry bones in a bag in my freezer until I have enough for a big batch of stock. Turn the bird breast-side up and apply the weight of your body to the palm of your hand to flatten the bird. Sprinkle the skin and cavity of the bird generously with sea salt; slather the chicken with 6 tablespoons of the spiced butter. If possible, salt and season the bird 4 to 10 hours before you are ready to cook and let sit in the refrigerator. About 1 hour before you plan to grill, let the chicken come to room temperature.
Heat a grill to medium-high heat or set up for indirect heat. Bring a kettle of water to a boil.
Meanwhile, grill chicken breast-side down, covered with vent open, until nicely charred, 10 to 15 minutes. Flip and cook 15 to 20 minutes more. Let the chicken rest for 15 minutes before carving.
While the chicken is resting, grill the spring onions until nicely charred, turning once, 8 to 10 minutes. Grill the fava beans until the pods begin to open, 1 to 2 minutes per side. Remove the vegetables from the grill and return them to the vinaigrette; give them a toss and taste for seasoning.
Before carving the chicken, slather on the remaining 2 tablespoons of spiced butter and top with the remaining lemon juice. Serve with the couscous and vegetables with vinaigrette.