How to Make It
In a large saucepan, melt the butter. Add the celery, carrots, onion, garlic, thyme and a generous pinch each of salt and pepper and cook over moderate heat, stirring occasionally, until the vegetables just start to soften, about 10 minutes. Sprinkle the flour over the vegetables and cook, stirring, until evenly coated and lightly browned, about 3 minutes.
Add the wild rice to the saucepan and gradually stir in the stock and water. Bring to a boil, then simmer over moderately low heat, stirring occasionally, until the vegetables are tender, about 30 minutes. Add the chicken and simmer, stirring occasionally, until the wild rice is tender, 10 to 15 minutes longer. Stir in the cream and season with salt and pepper. Ladle the soup into bowls and serve.