Asparagus soup can be achieved in all its glory from simply using the stems one cuts off at the bottom and the peels one throws away after peeling. I'm serious! The only things you need to truly achieve this are asparagus, an earth-friendly desire to not waste food, a good blender and a strainer. Thats it!
When I am cooking anything at home, I save the vegetable trimmings & scraps that most people throw away. I put it in a freezer bag that contains all my other trimmings which is everything from potato peels, onion skins and the hearts of a bell pepper to the tops & bottoms of leeks, celery and green onions. Once that bag is full I usually buy a chicken and roast it. I cut off all the meat and put the carcass in a big soup pot with as much of the bag that can fit in with it, some whole pepper corns and a bay leaf or two. I boil it for up to 4 hours on low (once boiling of course) with a lid and then strain it for the golden delicious broth it has made. As an extra task, I usually pick off all the bits of the chicken that you couldn't get with the knife and save it for both the dog and the cat, but that's optional of course.
I take that strained broth and I let it cool for a few hours. Then I pour it into one or two smaller, metal cooking bowls and set it in the freezer over night. In the morning you have a magical, healthy bouillon (stock) ice cube! You can flip it over in your hand and run warm or hot water over the bottom to loosen it from the bowl and put it in a freezer bag for 3-6 months. I defrost it whole in a pot for soups or I ice pick off chunks as needed for sauces. It's wonderful, it's healthy, it's cost-conscious and it's delicious!
So back to that soup....
If you want to make an asparagus soup that has a meatier flavor use this stock! You can of course use a veggie stock instead of a chicken one, or water if I am being honest. No one will come into your house and arrest you for your choices in stock making...
For most soups, I tend to follow the unspoken rule of the French, start with leeks instead of onions. Leeks are just a sexier flavor, I mean they are thinner and way more "in shape" than their round bellied cousin, the onion. But they also have such a delicate flavor that also still packs a punch. I find Americans do not use enough leeks. Let's change that, starting, now!
Depending on how many bunches of asparagus are being used, calculate one good sized leek per bunch, maybe even two, if small. They are so very flavorful!
1 good sized leek per bunch of asparagus
Trimmings from how ever many bunches of asparagus used
1 T butter
1 T olive oil
Salt & pepper to taste
1/2 t dried thyme per bunch of asparagus
Stock of choice (or water) that covers the asparagus until 2 1/2- 5 cm (1-2 inches) above the contents.
Chop the stems of the asparagus in rounds so they will cook faster and sauté them with the leeks in the oil and butter. You do not want them to brown, just simmer in the fat until soft, stirring occasionally. That should take between 5-10 minutes depending on how many bunches of asparagus used. Keep the lid on when not stirring and always let the water from the lid roll back into the pot. Next you will want to chop up the peels into about 2 inch strips. I find that it helps them break down easier when cooking and makes for less mess in the blender. Once accomplished, throw them in the pot. Mix them around to heat them up. Pour in your stock, add some salt & pepper and mix again. Bring to a boil with a lid on ands simmer for about 30 minutes.
In a proper blender, NOT a cuisinart or magi-mix, blend the contents once cooled a little. Blend it in batches carefully to not burn yourself. You want to really blend it well because to break up the peels is tricky work for the machine. They can get wrapped around the blade and leave a shredded nest mess. Once each batch is finished, using a fine strainer, strain the liquid into a bowl or pot (depending on whether you will be eating it right away or not). You can use the back of a spoon to push all the liquid through and continue until all the soup is gone.
Season it well. You can add any kind of cream or herbs if you desire.