In a soup pot over medium heat, cook the onion, garlic, ginger, carrot, cauliflower and sweet potato in 1/4 cup of the vegetable broth until fragrant and starting to soften, about 7-10 minutes. Add a splash more broth if it's starting to stick.
Add the turmeric, stir well and cook for a couple more minutes. Add another splash of broth if needed.
Add the rest of the vegetable broth and simmer lightly over low to medium heat until the cauliflower and sweet potato are tender, about 20 minutes.
Stir in the coconut milk.
For a creamy but chunky soup, carefully transfer roughly 1/2 to 3/4 of the soup to a blender and blend until completely smooth. Pour back into the pot with the rest of the soup. You can also just use an immersion blender right in the post to blend some of the soup. If you prefer a completely smooth soup, blend it all into smooth.
Serve right away topped with fresh chopped cilantro, a squeeze of lime juice and roasted chickpeas, if desired. Season with salt and pepper, if needed.