Thaw chicken in refrigerator over night or use fresh chicken. Remove the neck, gizzards, heart, etc from the center of the bird. Rinse the cavity with water. Cut the lemon (leave on rind) and onion into wedges and stuff into the cavity of the chicken. Brush olive oil all over chicken. Rub a crust of lemon pepper seasoning covering entire chicken. Place chicken on a rack. Bake at 325 degrees until meat thermometer reads 180 degrees and juices run clear. Let rest before carving.
*If your lemon-pepper seasoning does not contain salt or garlic, you may want add it to the seasoning to taste