prep time: 20 minutes
cook time: 30 minutes
2 pounds green asparagus
1 large onion - chopped
3 tablespoons unsalted butter
5 - 6 cups chicken broth
1/2 cup heavy cream
1/4 teaspoon fresh lemon juice
1. cut tips from asparagus 1 1/2 inches from the top and halve tips lengthwise if thick. set aside. cut stalks into 1/2-inch pieces.
2. cook onion in 2 tablespoons butter in a 4-quart heavy pot over moderately low heat, stirring, until softened. add asparagus pieces and salt and pepper to taste, then cook, stirring, 5 minutes. add 5 cups broth and simmer, covered, until asparagus is very tender, 15 - 20 minutes. set aside to cool.
3. while soup simmers, cook reserved asparagus tips in boiling slated water until just tender, 3 - 4 minutes, then drain. set aside.
4. puree soup in batches in a blender until smooth (use extreme caution when blending hot liquids as it can create pressure and pop the lid off). return to pan. stir in cream, then add more broth to thin soup to desired consistency. season with salt and pepper to taste. bring soup to a boil and whisk in remaining tablespoon butter.
5. add lemon and garnish with asparagus tips.