Step 1

Create a slurry by combining 1/2 cup of the cold water with flour in a medium bowl and whisk until well blended. Set aside.

Step 2

Pour remaining water and milk into a large pot and slowly bring to a boil.

Step 3

Add celery, onion, mushrooms, chicken bullion, thyme, fresh pepper, frozen vegetables and return to a boil.

Step 4

Partially cover and simmer on low until vegetables are soft, about 20 minutes.

Step 5

Remove lid, add potatoes and cook until soft, about 5 minutes.

Step 6

Add chicken, and slowly whisk in slurry, stirring well as you add.

Step 7

Cook another 2-3 minutes, until soup thickens, adjust salt and pepper to taste and serve.