In a small bowl, combine the spice blend, olive oil, and lemon juice. Set aside.
Spatchcock (split) the chicken: Remove any organs (sometimes found in a paper or plastic wrapping) from the inside of the chicken. Place the whole chicken breast side down on a large cutting board. Using kitchen shears or a large, sharp knife, cut along one side of the backbone, then turn the chicken around and cut down the other side. Remove the backbone, then flip the chicken over and firmly press down on the breastbone to flatten.
Place the chicken in a large roasting pan and season generously on both sides with the sea salt. Next, coat both sides of the chicken evenly with the oil mixture. Cover and marinate for at least 1 hour or overnight in refrigerator (overnight is recommended).
Preheat the oven to 375°F. Preheat a grill or grill pan to high heat.
Brush the hot grill or grill pan with the cooking fat, then sear the chicken skin side down for 8 to 10 minutes, until the skin is charred.
Transfer the chicken to a clean roasting pan, skin side up, and put in the oven for 1 hour, or until the internal temperature of the chicken reaches 165°F. (Test the temperature by inserting the thermometer into a meaty part of the leg, avoiding the bone.)
Remove the chicken from the oven and transfer it to a cutting board. Brush it liberally with olive oil and let rest for at least 10 minutes before serving