Pre heat oven to 450 degrees Fahrenheit

Chop parsley and mix with olive oil to make a paste

Place butter and half parsley/olive oil mix between skin and chicken breast

Rub chicken with remaining parsley/olive oil mix

Truss chicken

Cut onions into large pieces, place in a roasting pan, rest chicken on top of onions.

Cook chicken for 15 minutes at 450 degrees Fahrenheit

Lower heat to 350 degrees Fahrenheit and cook for 25 minutes per pound.