Fava Bean, Asparagus, and Pasta Soup

Ingredients

• 4 1/2 pounds unshelled fava beans (about 2 1/4 cups shelled)
• 1 tbsp olive oil
• 1/3 cup finely chopped shallots
• 1/3 cup finely chopped carrot
• 1/2 cup uncooked acini di pepe (about 3 ounces)
• 2 tbsp dry sherry
• 4 cups fat-free, less-sodium chicken broth
• 1 cup water
• 1 1/3 cup (1-inch) sliced asparagus
• 1 tbsp fresh lemon juice
• 1/4 tsp salt
• 6 tbsp grated fresh Parmesan cheese
• 2 tbsp chopped fresh chives