1. Oil the bottom of a large nonstick skillet and add sliced mushrooms.2. Cook the mushrooms for a few minutes on each side, until browned.3. Transfer the cooked mushrooms to a plate.
4. Sweat an onion in oil for a few minutes, until soft.5. Add white wine and simmer until reduced by half.6. Stir in flour and cook it briefly with the onions.7. Stir in vegetable broth.
10. Transfer half the soup to a food processor or blender.11. Blend the soup until smooth and creamy.12. Return the soup to the pot and stir it back in.