Preheat oven to 400 degrees. Line a baking sheet with foil and set aside.
In a large bowl, combine the leeks, sweet potato, tomatoes, carrots, garlic, olive oil, thyme, salt, and pepper. Mix well to coat the vegetables in the oil and seasonings. Spread in an even layer on the baking sheet and bake for 20 minutes or until the vegetables are soft and lightly browned.
Transfer the roasted vegetables to a large soup pot and add the vegetable stock. Use an immersion blender and blend until smooth. If you do not have an immersion blender, blend the mixture in a regular blender in small batches until smooth and transfer the pureed mix to a soup pot.
Once pureed, stir in the curry, turmeric, chili powder, and coconut milk and bring to a simmer. If the soup is too thick for your preference, add more vegetable stock or water until your preferred consistency is reached. Bring the soup for a simmer. Cover and simmer for 15 minutes, stirring occasionally. Ladle into serving bowls and serve hot!
Notes
OPTIONAL TIP: Serve with a side of crusty bread for dipping or top with garlic croutons.