Celery soup with cheese

• 1 head of celery with leaves
• 1 large potato
• 1 medium-sized onion

Separate the celery stalks, scrub well and then shred the stalks and finely chop the leaves. Peel and dice the potato. Peel and finely chop the onion.

Melt the butter in a large saucepan over low heat. Add the onion and fry gently for 5 minutes to soften but not brown. Add the celery and potato and cook gently for a further 5 minutes without allowing them to take colour. Add the stock a