Prepare the celery by cleaning and trimming it. (Keep the leaves for later)
Chop into small pieces.
Peel and chop the potatoes and place in a bowl of water. (to prevent them turning brown)
Chop the onion.
Melt the butter in a heavy bottomed pan.
Cook the onions and celery until soft, do not brown.
Add the water, milk, salt, and pepper and finally the potatoes.
Bring to a boil and reduce heat to simmer.
Simmer for 45 minutes.
Use a blender/liquidizer to make it smooth, or leave a little out so you can leave some little pieces as I have done in the photo but it is delicious either way.
Return to pan and gradually add the cream.
Serve with the celery leaves sprinkled on top. (Parsley could also be used if preferred)
Serve with your favorite crusty bread or croutons!