Sauté the onion, celery, and carrot in a large pot on medium heat for 5-7 minutes.
Add the ginger and garlic to the pot, stir, and cook for 2 minutes until fragrant. Add the vegetable broth, pumpkin purée, water, dried thyme, cumin, and salt & pepper to taste. Add the cauliflower (I used my hands to break it down into smaller florets).
With the lid slightly ajar, simmer the soup on medium-low heat for about 30 minutes or until the vegetables have softened.
Purée the soup in batches using your blender. I suggest letting the soup cool for a bit first.
The soup will be quite thick. You can add water to thin it out a bit (I added an extra cup). You may need to add more salt. Serve with a swirl of cream if desired.