Saute the onion in the butter in large and heavy pot. Add broth and bring to a boil. Add peas, return to a boil. Add mint, stir to wilt the mint, then puree the soup using an immersion blender and season to taste. May be served warm or chilled.
Notes
From Real Simple Magazine
Recipe by The Domestic Front at http://www.thedomesticfront.com/spring-pea-soup/