Cream of Asparagus Soup

2 pounds green asparagus

1 large onion, chopped (we used a combination of onion, shallots and leeks)

3 tablespoons unsalted butter

5 to 6 cups chicken broth

1/4 cup sour cream

1/4 cup cream

1/4 teaspoon fresh lemon juice, or to taste

Cut tips from 12 asparagus 1 1/2 inches from top and halve tips lengthwise if thick. Reserve for garnish.

Cut stalks and all remaining asparagus into 1/2 inch pieces.

Cook onion in a tablespoons butter in a 4 quart heavy pot over moderately low heat, stirring, until softened. Add asparagus pieces and salt and pepper to taste, them cook, stirring, 5 minutes. Add 5 cups broth and simmer, covered, until asparagus is very tender, 15 to 20 minutes.

While soup simmers, cook reserved asparagus tips in boiling, salted water until just tender, 3 to 4 minutes, then drain.

Using an immersion blender, blend soup until it is smooth or puree in batches in a blender.. Stir in cream mixture, then add more broth to thin soup to desired consistency. Season with salt and pepper. Bring soup to a boil and whisk in remaining tablespoon butter. Add lemon juice and garnish with asparagus tips. (We garnished with sour cream and red pepper).