This is hands down my favorite way to roast a chicken:
Butterfly it first. Save the back and inside things for the pan sauce
Marinate overnight in lemon juice, olive oil, smashed garlic, salt and pepper.
NExt day drain. PUt a pat of butter under each breast side skin. Heat oil in an oven proof skillet, and also at or just before put the chicken neck/back in a small pot with a few peppercorns, garlic, onion, celery, carrot, salt. Whatever things you have to flavor it. Pour 2 cups water or so and boil/simmer while chicken is going to cook. Place butterflied chicken skin down in hot oil and cook over medium for about 10 minutes until it is golden, then roast in 400 oven for 25 minutes. Then take out and carefully with tongs turn over, and roast longer skin side up until internal temp is done, another 15 minutes at least.
put chicken on platter and cover with foil
Drain your broth. Pour off pan juices in to a fat separator, then add to your broth, and keep the fat in the separator. Add a tblsp of fat back to the pan, saute a little onion or shallot, and add tblsp flour. Cook a minute, then slowly add broth, and boil/reduce at a rapid simmer until thick, about 5 minutes, add in any juices from the chicken platter by tipping it in to the pan, then off the heat stir in a pat of butter and some fresh chopped parsley. This is a fabulous and simple pan sauce. Carving a butterflied chicken is easier, and it's quicker too.
I acctually have a huge roasting pan and do two at a time....oh man that was a lot to type out LOL