Heat the butter in a large saucepan and
add the leeks and bay leaf. Cook over a
low heat for 8-10 mins or until the leek is
really soft, then stir through the potatoes
until coated in the butter. Pour over the
stock and cream and bring to the simmer,
then gently bubble for 10-15 mins until
the potatoes are really tender. If freezing
at this stage, slightly under-cook the
potatoes, then defrost and bring back
to a simmer to finish cooking them and
continue the recipe.
Add two-thirds of the smoked salmon,
stir through and season. Serve the soup
in deep bowls with the remaining smoked
salmon and snipped chives on the top.