Preheat a big pot with some olive oil.
When warm, add the minced garlic to the pot and fry for a few minutes. Until golden brown.
Next add the leek and fry for another minute.
Add the potatoes and cauliflower and stir together.
Next add the water, milk, stock cube and all the spices. Stir to combine and let the soup simmer for 25-30 minutes, until all the vegetables are soft.
When the soup is ready, mix using a hand mixer or add it to a blender and mix until smooth. Keep the soup warm.
Preheat two nonstick pans over medium heat.
Sauté the sliced mushrooms in one of the pans with some water in it. And then fry until golden brown when the water has evaporated. You can add some oil or vegan butter if preferred.
Add the roughly chopped pistachio nuts to the other pan and dry roast until warm and golden brown. (This step can be skipped)
Pour the soup into bowls. Top with fried mushrooms, pistachio nuts and chopped parsley.