2 tablespoons olive oil
1 onion, chopped
kosher salt and black pepper
4 cups low-sodium chicken broth
2 parsnips, chopped
1 butternut squash (about 1 1/2 pounds), cut into 1-inch pieces
2 tablespoons fresh lime juice
plain yogurt and lime zest, for garnish
Heat the oil in a medium pot over medium heat. Saute the onion, ½ teaspoon salt, and ¼ teaspoon pepper. Stir from time to time until tender, 6 to 8 minutes.
Add the broth, parsnips, squash, and 1 cup water and bring to a boil. Reduce heat and simmer until the squash is tender, 12 to 15 minutes.
Working in batches, puree in a blender until smooth. Stir in the lime juice.
Serve topped with the yogurt, lime zest, and pepper.