• 3 tablespoons butter
• 1 medium onion, diced
• 1 small russet or baking potato, diced
• 1 pound assorted mushrooms (oyster, crimini, shiitake, portobello, button), thinly sliced
• Salt and pepper, to taste
• 1/4 cup dry sherry
• 3 tablespoons flour
• 4 cups chicken stock
• 2 teaspoons chopped fresh thyme
• 1/2 cup heavy cream
• 1/2 cup plain yogurt or sour cream
• 1 tablespoon chopped fresh thyme (for garnish)

1. In a soup pot over medium heat, melt the butter. Add the onion and potato. Cook 5 minutes, stirring often.
2. Add the mushrooms, salt, and pepper. Cook, stirring, for 5 minutes. Pour in the sherry and bring to a boil. Lower the heat and simmer for 5 minutes or until liquid is reduced by half.
3. Sprinkle mixture with flour. Cook, stirring, for 1 minute. Add the stock, stirring constantly, until the mixture is smooth. Bring to a boil, lower the heat, and simmer for 15 minutes.
4. Remove from the heat. Add the 2 teaspoons thyme to the pot. In a blender, puree the soup in batches. Return to the pan and stir in the cream. Bring to a simmer over medium heat. Taste for seasoning, add more salt and pepper, if you like, and ladle into bowls. Garnish each one with yogurt or sour cream and thyme.

Note: Can be made vegetarian by substituting for the chicken broth.

Source: Boston Globe December 5, 2007 Keri Fisher