Peel and roughly dice/chop the vegetables and herbs. Melt butter in a large saucepan, add vegetables, toss in butter and cook gently for a few minutes, while stirring. Crumble the stock cubes into the 2 cups of water, stir to dissolve and add to the vegetables in the saucepan. Bring to the boil and simmer, covered, for about 20-30 minutes, or until all the vegetables are soft.

Cool a little, then put the vegetables and liquid (a couple of cups at a time) into a food processor or blender, and blend until smooth. Return the blended mixture to the saucepan, add the cream, salt and pepper to taste and the nutmeg (add extra nutmeg if desired). Reheat before serving, but don't boil. Serve with a spoonful of sour cream and chopped chives for garnish.