In a large pot over medium-high heat, warm the oil, and sauté the onion, garlic, ginger, turmeric, coriander, and 1/2 teaspoon of the salt for about 5 minutes, until the onion is soft and translucent and the spices are fragrant.
Add the carrots, butternut squash, broth, and 1/2 teaspoon of the salt. Increase the heat to high, and bring the soup to a boil. Reduce the heat to medium-high, and simmer, mostly covered for about 20 minutes, until the vegetables are tender. Stir in the coconut milk, lime juice, pepper, and the remaining 1/2 teaspoon of salt. Remove the soup from the stove, and allow the soup to cool slightly.
Transfer the soup to your blender, and blast on high for 30 to 60 seconds, until smooth and creamy. Add salt and lime juice to taste.