Make Ahead Tip: Prepare the soup (Steps 1 & 3), cover and refrigerate for up to 2 days. Top with prosciutto just before serving.
Kitchen tip: Hot liquids can splatter out of a blender when it's turned on. To avoid this, remove the center piece of the lid. Loosely cover the hole with a folded kitchen towel and turn the blender on. Better airflow will keep the contents from spewing all over the kitchen.
1 starch, 1 vegetable, 1 lean meat