Heat oil in a large pot over medium heat until shimmering
Cook the onions and salt until onions are soft and translucent, 8 to 9 minutes
Reduce heat to low, add garlic, and cook for 2 additional minutes
Add cauliflower, broth or water, coriander, turmeric, cumin, salt
Bring to a boil over medium-high heat, then reduce the heat to low
Simmer until cauliflower about 15 minutes
Purée the soup in a blender until smooth and then return the soup to the soup pot
Stir in the coconut milk and warm the soup
Serve with cashews and toast