Homemade chicken stock is the best for this. Also, if you can't locate any of the mushroom types indicated in the recipe, crimini (aka: baby bellas) will do just fine. Or, you can just leave them out all together.
Ingredients:
4 cups chicken stock, homemade preferred, divided
1 tablespoon cornstarch
3/4 cup enoki mushrooms or sliced shiitake mushrooms