Leeks, while in the onion family, have a gentler flavor that give this elegant soup a homey, comfort-food flavor.
- Melt the butter in a 5-quart saucepan over medium heat. Add the leeks and cook, stirring occasionally, until tender, 15 minutes.
- Add the potatoes and cook 2 minutes. Pour in the broth, increase heat to medium-high and bring to a boil. Reduce heat to medium-low, cover, and simmer until potatoes are very tender, 25 minutes.
- Remove from the heat and let cool 10 minutes. With an immersion blender or food processor puree the soup, being careful not to over process or the soup could become gluey.
- Return the soup to the saucepan and stir in the heavy cream; bring to simmer over medium heat and cook 5 minutes. Remove from the heat and stir in the chives, salt and pepper.