In a large 6 quart dutch oven or similar sized pot, steam saute the onions in a little vegetable broth with a pinch of red pepper flake. Add more broth as needed. Cook until softened.
Add the cauliflower and carrots along with the rest of the broth. Bring the soup to a bubble and simmer until the veggies are softened.
Season with the ginger, turmeric and curry powder.
Carefully use a stick blender to puree the vegetables. Add more water or vegetable broth as needed to help smooth out the texture.
Stir in the coconut milk. Taste and adjust the seasoning.