Melt the butter in a large pan. Peel and finely chop the onion and cook gently in the butter for about 5 minutes without colouring. Peel and chop the carrots and potaotoes and add them to the pan along with the stock and the chopped pumpkin flesh. Bring to boil and simmer gently for about 20 minutes until the vegetables are cooked right through.
Liquidise until well blended then add the milk, grated nutmeg, demerara sugar and salt and freshly ground black pepper to taste. Serve with warm bread rolls or parmesan toasts.