Step 1

In a medium pot, heat oil over medium-high. Add onion and cook until translucent, 6 minutes. Add squash, pears, and 4 cups water; season with salt and pepper. Bring to a boil; reduce to a rapid simmer and cook until squash is soft, 20 to 25 minutes.

Step 2

In batches, fill a blender halfway with soup and puree with yogurt until smooth (use caution when blending hot liquids), transferring to a clean pot as you work. Season with salt and pepper; serve with chives and a drizzle of olive oil.