method
1. Peel and finely chop the onion. Melt the butter in a saucepan, add onion and fry till transparent. Stir in the stock and wine and bring to the boil slowly.
2. Blend the cornstarch with a little water and add to the pan, stirring constantly. Bring back to the boil, stirring, and cook for 3 minutes.
3. Add the milk, salt, pepper and grated cheese. Stir over a very low heat till the cheese has completely melted. Taste and adjust seasoning, then pour into a warmed tureen.
Serve immediately garnished with lots of croutons.
