Add the olive oil, cauliflower, onion, garlic, and vegetable broth to a slow cooker and turn to high heat for 3-4 hours, or until the cauliflower is very soft.
Add the coconut milk and salt and blend with an immersion blender, or transfer to a food processor or blender and blend until smooth.
Pour the soup back into the slow cooker, turn the slow cooker to warm and stir in the cheese. Serve hot.