I just found this recipe yesterday. Hope it is what you are looking for.

Enjoy!

Chili's Grill & Bar Chicken Mushroom Soup

1/4 cup ( 1/2 stick) margarine
1/4 cup diced yellow onion (cut into 1/4-inch pieces)
1/4 cup diced carrots (cut into 1/4-inch pieces)
1/4 cup diced celery (cut into 1/4-inch pieces)
3 cups sliced mushrooms (about one 8-ounce package, cut into 1/8-inch slices)
1/2 cup flour
5 1/2 cups chicken broth
Pinch of dried tarragon
1/4 teaspoon dried thyme
1/2 teaspoon white pepper
1 teaspoon black pepper
1/2 teaspoon hot pepper sauce
1 tablespoon chopped fresh parsley
3 cups half-and-half cream
1 1/2 teaspoons lemon juice
3/4 pound diced cooked chicken
Melt margarine in large heavy pot. Add vegetables and saute until tender over medium-low heat. Slowly sift flour over vegetables and let cook briefly, stirring regularly. Do not let flour brown. Slowly add chicken broth to vegetable-flour mixture, stirring constantly. Add herbs, pepper sauce and parsley and stir well. Simmer 10 minutes. Stir in half-and-half, lemon juice and chicken. Bring to simmer and cook 10 minutes. Serve immediately. Makes 3 quarts.
Appeared in the Milwaukee Journal Sentinel on January 9, 1999