Butterflying chicken helps it to cook much more quickly, and evenly too for that matter. It's also a bit easier to whack apart and serve when it's done. Butterflied chicken can be roasted, as I've done here, or it can be done on the grill. Martha Stewart has grilling instructions at her site. I used her suggestion for the rub, and it was quite good.
To roast instead of grill:
Preheat oven to 450. Place chicken skin side up in a large roasting pan and cook until the skin is golden and crispy. Check the internal temp; it needs to be 165. It should take about 45 minutes. Cover with foil if it takes longer. Let chicken rest before carving.