- Preheat the oven to 200°C. Grease a 1.5 litre capacity baking dish with butter
- Melt the butter in a small frying pan and gently cook the leek for 15 mintues until tender.
- Whisk the egg white in a clean bowl until stiff but not dry. In a separate bowl lightly mix the egg yolk.
- Comibine the egg yolk, leeks, flour, herbs, cheese, salt and pepper iin a large bowl and gently fold in the egg white.
- Pour the mixture into the baking dish and cook for 10 minutes until puffed, golden and set.