Ramp Soup

Directions

1. 1
   Trim roots from ramps and slip off outer skin on bupounds if loose. Cut green tops from ramps and coarsely chop enough greens to measure 3 cups (reserve remainder for another use). Thinly slice ramp bulbs, including pink stems.
2. 2
   Cook ramp bulbs, onion, white pepper, and 1/2 teaspoon salt in oil in a large heavy saucepan over medium heat, stirring occasionally, until softened, about 10 minutes. Add wine, then boil over high heat, stirring occasionally, until evaporated completely. Add broth and simmer, partially covered, stirring occasionally, until onions and ramps are very soft, about 20 minutes. Stir in ramp greens and boil 1 minute.
3. 3
   Working in batches, puree soup in a blender until very smooth, about 1 minute per batch (use caution when blending hot liquids), then strain through a fine-mesh sieve into a large heatproof bowl, pressing hard on and then discarding solids. Return soup to cleaned pot and bring just to a boil. Whisk in cheese and butter until smooth. Season with salt.