Heat the oven to 425°F. Spread the carrots on a baking sheet and sprinkle with the chili powder. Roast for 30 minutes or until soft and slightly charred.
Meanwhile, heat the olive oil in a medium saucepan. Set over medium heat Add the onion and cook until it’s soft and light golden brown, about 8 minutes. Add the celery and ginger and cook 1 minute. Stir in the vegetable broth and bring to a simmer.
Add the roast carrots and simmer 10 minutes, or until very soft. Transfer to a blender, working in batches if needed, and blend into a smooth puree.
Divide the soup between four bowls and top with coconut milk yogurt and fresh mint.