In 3-quart saucepan, melt butter over medium heat. Cook sliced mushrooms in butter about 10 minutes, stirring occasionally, until mushrooms are golden brown. Sprinkle with flour and salt. Cook, stirring constantly, until a roux forms. Gradually stir in broth; heat until simmering.
Spoon out all of the broth and about half the mushrooms into a blender. Be very careful because hot liquids in a blender can explode and burn you. Make sure the hot air from inside the blender can escape easily by taking out the removable center part of the blender lid and loosely place a kitchen towel over it. Blend on low working up to purée and blend until smooth. Add this back into the saucepan.
Stir in whipping cream and sherry. Sprinkle with salt and pepper. bring back up to a simmer and serve.
Servings 0