Step 1

Place the parsnips and carrots into a large pot and cover with salted water. Bring to a boil over high heat, then reduce heat to medium-low, cover, and simmer until tender, 15 to 20 minutes. Drain; return vegetables to pot. Turn heat to low, stir in the chives and 3 tablespoons of butter.

Step 2

Begin to puree mixture using an immersion blender. Add 3 tablespoons of butter and continue to puree until mixture is smooth. Season with salt and pepper to taste.