Preheat oven to 375°F; prepare roasting pan.
Pat chicken dry; tuck wings, tie legs.
Mix oil, butter, salt, pepper, garlic powder, paprika, thyme, and rosemary; taste and adjust; rub on chicken.
Stuff cavity with lemon, garlic, and onion.
Roast 1.5–2 hours, basting every 30 min, until 165°F.
Rest 10–15 min; serve on a white ceramic platter with rosemary, wine, and potatoes.