- Cook onion in butter until soft.
- Add flour and cook, stirring, for 4-5 minutes.
- Gradually add stock, stirring.
- Add cream and wine and bring to a boil.
- Reduce heat to a simmer, add asparagus and nutmeg and cook for 15-20 minutes.
- Puree in batches in a food processor or blender.
- Add salt and pepper to taste.