This soup is deceptively simple, but really amazing and super-quick to make. I found the recipe on Epicurious.com and tweaked it a bit. This recipe makes enough for 6 folks.
1/4 cup (1/2 stick) butter
1 cup sliced shallots (about 6 large)
2 pounds asparagus, trimmed, cut into 2-inch lengths
2 teaspoons ground coriander
4 cups vegetable broth
1/4 cup plain yogurt
1/2 teaspoon fresh lemon juice
1/4 teaspoon finely grated lemon peel
Melt butter in heavy large saucepan over medium heat. Add shallots; sauté until golden brown, about 5 minutes. Add asparagus and coriander; stir 1 minute. Add vegetable broth and simmer until asparagus is tender, about 5 minutes. Cool slightly. Working in batches, puree soup in blender. Season with salt and pepper. Keep warm.
Stir yogurt, lemon juice, and lemon peel in small bowl. Divide soup among bowls. Top with dollop of lemon yogurt and serve.