Heat oil in a large pot; add leeks and onion and sauté until they soften.
Add butternut, apple and black pepper.
Add KNORR Vegetable Stock Pot, milk and water, and add to the soup mix.
Simmer for 25-30 min until the butternut is tender.
Once cooked, place in a liquidiser and puree until smooth.
Serve with a swirl of cream and garnish lightly with black pepper.