Rinse the whole chicken thoroughly under cold running water.

Remove any excess fat and pat dry with paper towels.

Cut the chicken into pieces, including the breasts, thighs, wings, and drumsticks. If desired, reserve the back and bones for extra flavor.

Fill a large pot with water and bring it to a rolling boil.

Gently add the chicken pieces to the boiling water and blanch for 1-2 minutes to remove impurities.

Remove the chicken from the pot and rinse it under cold water to stop the cooking process. Set aside.

In a separate large soup pot or a Dutch oven, heat the vegetable oil over medium heat.

Add the chopped onions, ginger slices, crushed garlic, and half of the chopped green onions.

Sauté until the onions become translucent and the mixture releases a delightful aroma.

Pour the 10 cups of water into the pot with the sautéed aromatics.

Add the blanched chicken pieces, carrots, celery, and optional Chinese mushroom (if using).

Stir in the soy sauce, oyster sauce, and Shaoxing wine or dry sherry.

Increase the heat and bring the soup to a boil.

Once boiling, reduce the heat to low, cover the pot, and let the soup simmer gently for about 1 to 1.5 hours. This slow simmering process allows the flavors to meld and the chicken to become tender.

After the simmering time, taste the soup and add salt and white pepper powder to your preference. Adjust the seasonings as needed to achieve your desired flavor profile.

Add the remaining chopped green onions and a teaspoon of sesame oil to the soup, giving it a final stir.