Clean and slice the leek and sweat in a little butter. Add half the turkey stock and the potatoes. As my potatoes were already cooked, I was able to blitz the soup with my hand-held blender; if they are raw.
Simmer until the potatoes are cooked and THEN blitz the mixture with a blender or food processor.
Add the vegetables and tarragon and bring to a boil.
When the carrots are tender, add the turkey meat.
Bring back to a boil and then turn down the heat so that the soup simmers. Pour a spoonful of the hot soup into the cream, mix and then add the cream to the soup. (This should keep the soup from curdling).
Stir well and taste for salt and pepper. You may well find it needs a bit of salt. A good grinding of pepper will also add a little bite to the velvet creaminess.