In a pot with a tight fitting lid, place the onion, apple, carrots and half the ginger at the bottom. Arrange the napa cabbage on top and place the whole chicken on top of the cabbage. Season with 1 teaspoon kosher salt. Place remaining slices of ginger on top.
Cover the pot and let cook on medium low to low heat for 90 minutes until chicken is cooked through and tender.
Meanwhile, place the green onion, ginger and salt into a heatproof bowl. In a small saucepan on medium high heat, heat the oil until you see a whisp of white smoke. Carefully pour it over the green onion and ginger mixture and mix well. Set aside.
Once the soup is done, season with more salt if needed.
Serve in individual bowls along with the dipping sauce for the chicken.