Simple and satisfying, this will remind you how good mushroom soup can be.  A little goes a long way with this rich soup, so serve small portions.

1. Melt the butter in a large heavy saucepan over medium-high heat. Add the mushrooms and sauté until tender and browned. Stir in the flour, salt, pepper and mustard and cook, stirring continually, for 1 minute.

2. Add the broth and cook, stirring continually, until thickened, 5 to 10 minutes. Stir in the half-and-half and sherry and cook until heated through. Ladle the soup into bowls and sprinkle with the chives.

Variation
For an even richer soup, use 2 cups half-and-half and 2 cups broth.