1) Simmer leeks, potatoes and cauliflower in 4 cups stock until potatoes and cauliflower are tender. About 20 - 30 minutes
2) Use a hand mixer or blender stick to mash the potatoes and cauliflower in the stock until mostly smooth or to preferred consistency.
3) Add grated cheese and stir. Thin soup further to desired consistency with milk. Add salt and pepper to taste. Serve into bowls, and top each serving with grated cheese and chives, if desired. I enjoy this soup with broccoli, so I steam or roast broccoli and serve it too.