Whisk together oil, turmeric powder and ginger powder in a medium bowl; add cauliflower and toss to coat. Place the cauliflower on a baking sheet and roast for 20–25 minutes, or until tender.
Place butter and leeks in a soup pot over medium heat and sweat until soft.
Add the potato and roasted cauliflower to the leeks, cover with coconut water and cook until tender, 12–15 minutes.
Remove pot from heat and place a few ladles of liquid into blender, adding a few cashews with each batch until all is incorporated.
Pour small, mixed batches back together in pot and whisk in almond milk.