Creamy Asparagus Soup

3 lbs fresh asparagus, ends trimmed and cut into 1-inch pieces
1-14.5 oz can chicken broth
1 small onion, chopped
1 Russet potato, peeled and cut into 6 to 8 large chunks (see note below -- cut into smaller pieces if you plan to leave the potato in the soup)
salt and pepper, to taste
1/2 C half & half, heavy cream, or sour cream (at room temperature)
optional garnish: chopped fresh chives or fresh dill; croutons; freshly-grated Parmesan cheese

In a heavy pot, combine asparagus, chicken broth, onion, and potato. Season with salt and pepper. Simmer, covered, until asparagus is very tender but still green, 10 to 15 minutes. Remove the potato chunks. Using an immersion or regular blender, puree soup. If using a regular blender, be sure to pause and remove the lid a few times to allow the steam to escape (so that it doesn’t explode). Return pureed soup to the pot, stir in the cream, and warm over low heat (do not boil). Season with salt and pepper to taste; garnish with herbs or other optional toppings