Prepare 450g (1lb) leeks .
Melt 50g (2oz) Butter in saucepan and fry gently for about 5 minutes until tender.
Stir in 25g (1 oz) medium oatmeat and 1.2lt (2pt) stock.
Bring to the boil and simmer for 20 minutes.
Just before serving stir in 100g (3 1/2oz) grated mature cheddar cheese, season to taste and ladle into bowls.
Serve immediately with sprinkled chopped parsley.