*Note: the original recipe specified dried thyme.
Preheat the oven to 425 degrees.
If using a whole chicken/spatchcocking: Place chicken on the cutting board breast side down. Use kitchen shears to cut down the length of the spine on both sides. Discard the spine.
Turn the bird breast side up. Gripping the 2 cut sides where the spine used to be, open up the bird, pressing down firmly at the center to flatten it.
For chicken pieces: Rub the spice mixture all over the chicken pieces and brown on both sides for 5 minutes each side.
In a small bowl, mix together the salt, garlic powder, thyme (or other dried herb of choice) and black pepper. Rub the mixture evenly over the entire chicken.
Set a large cast-iron skillet on a burner over medium-high. When the skillet it hot, add the chicken breast (or chicken pieces) side down. Let the chicken brown for 5 minutes, then use tongs to carefully flip the bird so the breast side is up. Brown the other side 5 minutes.
Set the skillet in the oven and roast for 30 to 40 minutes, or until the thickest part reaches 165 degrees. Depending on if you use a whole chicken, bone-in chicken pieces or boneless, roasting time will vary. It only took about 25 minutes for our chicken pieces to roast all the way through.
Either serve immediately or let cool and refrigerate for use in a picnic.