Preheat the oven to 425 degrees.
Remove chicken giblets out of the cavity and rinse the chicken. Pat dry with paper towels. Mix together the butter and 2 cloves of minced garlic together until well combined. Carefully, loosen the skin covering the breasts and coat the breasts with the butter mixture. Coat the chicken with olive oil cooking spray and season the entire bird with sea salt, freshly cracked pepper, and garlic powder, to taste.
Season the inside of the cavity with sea salt, freshly cracked pepper, and garlic powder, to taste then place the onion, garlic cloves, and fresh parsley into the cavity. Place the bird on a roasting rack in a roasting pan.
Place a meat thermometer into the thickest part of the thigh without touching the bone. Place the chicken into the oven and roast for 1 1/2 hours or until the temperature reaches 180 degrees. Remove the chicken from the oven and let the bird rest with a tin foil tent for at least 10 minutes before carving. Enjoy.