Take a multicooker, open and unlock the lid by turning the handle to the unlock position. Add chicken, celery, onion, garlic, thyme, salt, pepper and water into the cooker. Close and lock the lid by turning the handle to the lock position.
Press the [MENU SELECTION] button to select the [MULTICOOK] function. Set the cooking time for 15 minutes and temperature 120 degrees then press [COOK]
Once the cooking time finished, open and unlock the lid. Take out the chicken and move it on to a cutting board and allow it to cool. Strain the stock by pouring through a large sieve, discard the solids. Save the stock on to a separate bowl
Cut the chicken into bite-size pieces. With the lid still open, turn the handle to the lock position. Press the [MENU SELECTION] button to select the [MULTICOOK] function. Set the cooking time for 5 minutes and heating level 3 then press [COOK]
Add onions and carrot into the cooker. Stir-fry until the onions are translucent for 2 minutes. Pour the stock back into the cooker then add the cooked chicken, celery and parsley. Let it simmer for a while until the cooking time is finished.
Ladle the soup into a bowl and garnish with green onions.