Cream of Asparagus Soup

This is from the old (1977) Moosewood Cookbook by Mollie Katzen. I actually follow this recipe, except for decreasing the butter. Most cream/white sauce recipes use equal amounts of butter and flour, but I don't find that to be necessary. I just use enough butter to saute without burning, probably about 2 Tbsp for this soup. I'm not fussy about getting the exact amount of asparagus called for, either. If I have a little more, that's fine. This is delicious with skim milk--creamier milk makes it more luxurious.

Cream of Asaparagus Soup
1 1/2 pounds fresh asparagus
1 1/2 cups chopped onion
butter as needed
salt
6 Tbsp flour
2 cups water or stock
4 cups scalded (heated almost to a boil) milk
1/2 to 1 tsp dill weed
1 tsp salt
white pepper
dash of tamari or soy sauce

• Break off the tough asparagus bottoms and discard them (compost pile!!). Cut off the tips and set them aside. Chop the stalks, and cook them with the onions in the butter, salting them lightly.
• After about 8-10 minutes, when onions are clear, sprinkle in the flour. Continue to cook over lowest possible heat (use a "waffle" heat absorber if you have one) for 5-8 minutes.
• Add water or stock. Cook 8-10 minutes, stirring frequently, until thickened.
• Puree the sauce bit-by-bit with the milk in the blender. Blend it until thoroughly smooth. Return the puree to a kettle, preferably a double boiler, and add dill, salt, white pepper, and tamari.
• Heat the soup very gently--don't boil it or cook it. As it heats, steam or saute the asparagus tips until tender but still very green. Add these, whole, to the soup.
• Serve as immediately as possible.

Note: My mom gave me an immersion blender (you stick the blender in the pot rather than transferring the soup) which makes the pureeing MUCH easier. Also, I don't bother with a double boiler; I'm just careful not to scorch the soup.