seperate stalks of celery from base and trim, reserve leaves for garnish- trimmed stalks should weigh 450g, trim outer stringy bits. scrub rest in cold water and drain, slcie across in thinnish slices.
in medium saucepan melt butter, stir in celery, potato and onion, stir everyting around to coat with butter put on lid turn heat low and sweat for 10 minutes.
uncover add stock and bring to simmering point cover again and cook for 30 minutes test veg for tendereness if not recover and cook until they are.
whilst this is going on prepare croutons heat olive oil in large frying pan and add cubes of bread keep them moving turning around and upside down until they have turned a deep golden brown colour and have become very crunchy and crispy, drain on kitchen paper.
remove saucepan from heat stir in cream then liquidise soup with crumbed stilton until quite smooth, retunr soup to rinsed out pan and reheat very gently taking care not to boil.
taste and season serve with croutons and celery leaves.