Trim the asparagus and cut into 2" pieces.
In a large pot heat the olive oil and add the chopped onions and saute until translucent.
Add the flour and mix.
Add the asparagus and saute for about 2-3 minutes.
Add the ground coriander ,salt and pepper.Stir for a few minutes.
Add the broth and bring to a boil.
Reduce the heat, cover and let it all cook for about 20-25 minutes.
Once slightly cooled puree the soup in a blender.
Chill in the fridge for at least 3 hours or even overnight.
Serve chilled with a dollop of sour cream and your favorite bread.