My Simple Spargelsuppe. I call it that because I never ate asparagus soup until I wandered around Germany in spargel season in 2003. I wasn't sure I'd like it, but one day we stopped in a village where it was the only thing on the lunch menu, with crusty bread. I discovered I loved it. We don't get those big whitish German asparagus, but our local green ones with the purplish heads aren't bad either.
This is very similar to the mushroom soup. I usually buy my asparagus in small bunches, which is the way they appear in our supermarkets:
I buy three bunches, eat a couple and reserve one for soup.
Soup preparation is almost identical to the mushroom soup.
Fry an onion in olive oil and butter until caramelising. Add the roughly chopped asparagus spears, reserving the tender tips, and cook until tender. Add about a litre/quart of stock (chicken or vegetable) and simmer for about 30 minutes. If you aren't sure how much stock to use, begin with a little less. You can always add more later. Season with salt and grated pepper.
Puree the soup and return the reserved tips to the soup. Return to the stove for five minutes to cook the tips, stirring if necessary to ensure the thicker soup does not stick. Adjust for consistency; second time around you will know exactly how much stock to use.
I am a parsimonious type that hates waste. When I eat the other bunches, I keep in the fridge the woody stub that I snap off the spears. For the soup I slice off and discard the really woody ends from the stubs and simmer the slightly softer remainders in some chicken stock while I'm preparing the rest. I puree the result carefully so that any stringy bits disappear and then add that in with the stock to the main pot at the appropriate time. This makes two or three serves.
Add a dollop of cream to each bowl when serving.
PS I have a few variants of this recipe. My favourite is to add an equal portion of broccoli, reserving some small florettes in the same way that I reserve the asparagus tips, for an asparagus and broccoli soup. I adjust the stock quantity accordingly. I also vary flavour using nutmeg and/or garlic.