I like to peel the stalks of the asparagus, but keep the peel.
I take off the bottom inch or two of the asparagus where it becomes stringy.
Simmer the asparagus trim in 4 cups chicken stock or water and chicken boullion.
I simmered this on low for about 2 hours.
Next I put the peelings and butts in the blender and blended it for a minute. Caution , hold down the lid of the blender with a towel. Also I do it in 2 batches.
Then strain the juice back into the sauce pan, and discard the stringy mass left.
Simmer the potatoes and onions in this stock for 15 to 20 minutes until the potatoes are tender.
return the soup in the blender and blend on high till very smooth, about 2 minutes in the blender,
The longer you blend the smoother it will get.
Top with yogurt, and a little chili oil and chopped chives.