Step 1Snap the tough ends off the asparagus spears. Wash the spears well and chop or break into roughly 1-inch pieces. Set aside.
Step 2Melt the butter in a heavy soup pot over very low heat. Add the shallots and one-eighth teaspoon of salt, mix well, cover the pan and simmer until the shallots are soft, about 5 minutes. Add the asparagus and another pinch of salt, cover the pan and simmer until the pieces are tender, about 10 minutes. (This concentrates the flavor.)
Step 3Add the stock to the pot, raise the heat to bring the stock to a slow simmer, cover and simmer about 15 minutes, until the asparagus is very soft.
Step 4While the asparagus is cooking, combine the creme fraiche and herbs in a bowl or the container of an immersion blender. Process until the herbs are finely chopped and the mixture is well blended. Season to taste with salt and set aside.
Step 5When the soup is finished, process in the pot using the immersion blender to make a smooth puree. Season with pepper to taste and more salt if needed.
Step 6To serve, ladle into individual bowls and top each with a large scoop of the herb cream. You can swirl it in or serve it as is. Makes about 8 cups.