PREPARATION:

1. The night before roasting: Combine the lemon, onion, garlic and all but 2 pieces of rosemary in a bowl. Season with a generous pinch of salt and some grindings of pepper. Place all of the mixture inside the bird cavity, and a few cloves garlic in the neck cavity. Slip one piece each of rosemary under between each side of breast and skin. Sprinkle entire outside of bird with salt. Wrap bird in plastic and refrigerate overnight.
2. Preheat oven to 425°. Unwrap bird, pat off any moisture and bring to cool room temperature. Place bird in cast iron skillet or roasting pan (just big enough to hold bird comfortably), smear breast with butter and give a light shower of salt.
3. Roast bird until a thermometer inserted into the thigh reads 165, approximately 45 minutes - 1 hour. Skin will be appealingly browned. Let bird sit 10 minutes before carving. Tip juices from cavity into the pan, remove bird to cutting board or platter to carve. Add parsley to pan juices and pour over carved bird.