cooking and sets the color) and set aside.
Pour out the water from the first pot, wipe it dry (no need to
scrub it), and melt the butter on medium heat. Add the onions and
a pinch of salt and lower the heat. Cook, very gently, stirring the
onions every so often to avoid browning.
When the onions are translucent and soft (about 20 minutes),
add the garlic, the rest of the asparagus, the tarragon, and the
nutmeg. Add enough water to cover everything but not too much
water (you can always add more later). Season with salt, tasting
the water to make sure it has flavor (the water is what will flavor
the asparagus). Bring to a full boil, lower to a simmer, and cook
until the asparagus is extra tender (you should be able to easily
mash it against the side of the pot with a wooden spoon). Add the
spinach and remove from the heat.
When the soup has cooled slightly, add to a blender and puree*
until you no longer see the dark green flecks from the spinach. (Be
careful when blending anything hot! Leave an opening at the top of
the blender, covering with a dish towel.)
Strain through a fine-mesh strainer into a separate pot (or into
the same pot, but clean it first). You can chill the soup at this
point and serve it cold later on or, if you’d prefer to serve it hot,
you can reheat it with a little water. To serve hot, ladle the soup
into warm bowls and garnish with the asparagus tips and with
some crème fraîche and chives, if desired.
* Danko uses dried tarragon; I prefer fresh. The choice is yours.