Wash chicken and pat dry with paper toweling. (It goes without saying, pull off any errant pieces of skin or feathers/quills, and remove giblets from the cavity if there are any)
Coarsely chop the bulb of garlic (don’t bother to break apart the cloves or peel them)
Remove rosemary needles from 4 of the stems; reserve the rest for later.
Chop lemons into quarters.
Put the chopped garlic, chopped lemons and chopped rosemary into the chicken cavity and secure the legs with twine.
Rub the skin of the chicken generously with soft butter or oil, and season with salt and pepper. Tuck chicken wings behind the back and place face up on a roasting rack.
Roast the chicken for 15 minutes at 475F then reduce heat to 375 and cook until chicken reches 165F on a instant read thermometer in the thickest part of the thigh (or until the juices run clear), about 60-75 minutes.
Allow chicken to sit for 15 minutes before carving (this lets the juices settle into the meat and brings the temp up to right where you want it- about 170F.)
Garnish with fresh rosemary stems before serving if desired.