Preheat your oven to 350 degrees F (175 degrees C).

Pat the chicken completely dry inside and out using paper towels.

Place the chicken in a roasting pan. Season the skin and the inside of the cavity generously with onion powder, salt, and pepper.

Place 3 tablespoons of the butter inside the chicken cavity along with the celery pieces.

Take the remaining butter and place small dollops all over the outside of the chicken skin.

Bake uncovered in the center of the oven for about 1 hour and 15 minutes. The chicken is done when the juices run clear and an instant read thermometer inserted into the thickest part of the thigh reads 165 degrees F (74 degrees C).

Remove the pan from the oven. Use a spoon to baste the chicken with the melted butter and drippings from the bottom of the pan.

Cover the chicken loosely with aluminum foil and let it rest for 30 minutes before carving. This step is essential for juiciness!