Heat the olive oil in a large saucepan over medium heat. Sauté the onions until they are completely soft and translucent, about 8-10 minutes. Add the asparagus, salt and pepper and continue cooking until the stalks turn bright green, about 4-5 minutes. (Reserve about 1/4 cup asparagus to garnish the soup.

Increase the heat and add the stock. Once the stock is boiling, reduce the heat and simmer until the asparagus is tender, about 8-10 minutes. Then add the spinach stirring until it has wilted, about 2 minutes. Allow the soup to slightly cool.

In batches, transfer the soup to a blender to puree. Strain the soup in a fine mesh sieve. Cool to room temperature and then chill in the refrigerator before serving.

Top each bowl with the reserved asparagus, salt, pepper, chives and parsley.