In a saucepan add water and chicken breast and bring to boil. After boiling, reduce the heat to low and simmer the chicken breast for 10 minutes. Remove the impurities on the top of water. After 10 minutes remove chicken breast from saucepan. Shred the chicken breast on a cutting board with fork and knife. It is okay if the chicken is slightly undercooked, we will cook it again in soup. Save 500 ml of the water for soup.
In the same saucepan melt the butter, then add mixed vegetables and celery stalk and sauté for 1 minutes. Then add flour and stir frequently for 2 minutes.
Add milk little by little while mixing so there is no lump on the saucepan. Then add previous water from cooking the chicken breast. Bring to boil.
Add chicken stock powder, onion powder, garlic powder, salt and blackpepper. Stir until combined. Boil until the preferred consistency. Then add shredded chicken breast and celery leaves. Boil for 1 minute.
Turn off the heat and creamy chicken soup is ready to serve.