1. Heat oil in a large stockpot over medium heat. Add leeks and cook, stirring occasionally, until softened, about 12 to 15 minutes. Add beans and cook 1 to 2 minutes more, then stir in thyme, salt, and pepper. Add broth, cover, and bring to a boil. Reduce heat and simmer 5 minutes.
2. While soup simmers, trim the tips off 6 asparagus stalks and reserve, then slice the rest of the stalks into 1/2-inch pieces. Set aside.
3. Use an immersion blender to puree the soup. Alternately, working in batches,transfer the soup to a blender and puree until smooth, then return to the pot.
4. Add sliced asparagus to the pureed soup. Bring to a simmer over medium-high heat. Simmer until asparagus is crisp-tender, about 3 to 4 more minutes.
5. Ladle soup into 6 bowls. Garnish each with a reserved asparagus tip and a pinch of thyme if desired.
Source: Hannaford fresh Magazine, March - April 2013