Melt coconut oil in a large soup pot over medium heat. Add salt and leeks and sauté for 5 mins. Add garlic, ginger and cauliflower and sauté for another 5 mins. Add cashews and broth. Bring to a boil, reduce heat, cover and simmer for 30 mins.
Remove from heat and let cool for at least an hour. Puree in a high speed blender until creamy.
Season with vinegar or lemon juice, and salt to taste.
Serve with hot sauce if desired.