Cut potatoes, celery and carrots in same size small cubes. Dice onion. Dice cooked chicken.
In a large soup pot add 6 tbsp of butter and saute` carrots, celery, and onion till tender.
In another pot boil diced potatoes until tender. Set aside.
Once carrots, onion and celery are tender, add 6 tbsp of flour and mix around to make paste. Add milk and mix to make a "gravy", now add warm chicken stock. Mix together well. Add garlic and onion granules, pepper, thyme, and poultry seasoning as well as peas. Simmer for about 20 min. Add potatoes and chicken and salt to taste. Simmer about 10 min. more.