Step 1

Place cold water and flour in a blender and blend until smooth; pour into a medium pot and set heat to medium.

Step 2

Add celery, mushrooms, chicken bullion and butter and bring to a boil.

Step 3

Cover and simmer until vegetables are soft, about 20 minutes.

Step 4

Remove celery and a cup of soup and place in a blender, blend until smooth, then return it to the pot and simmer a few minutes.