Preparations:

1. In a large pot, heat butter over medium heat until it begins to brown and turns fragrant, 3 to 4 minutes. Add sage and cook one minute more.
2. Add mushrooms and stir to coat, then saute until mushrooms are tender and lightly browned, 4 to 5 minutes.
3. Stir in stock and bring to a simmer. Cook 4 to 5 minutes more.
4. Transfer to food processor or blender (in batches, if your processor is not large enough). Blend until smooth.
5. Return to pot and stir in cream. Serve immediately.