Heat the oven to 200C/400F/gas 6.
Melt the butter in a small saucepan, add the cornflour and plain flour and stir with a wooden spoon to form a paste. Gradually whisk in the milk, season and simmer gently for three minutes until thickened.
Removing the pan from the heat, add the spring onions, chives, Stilton and egg yolks and stir to combine. In a clean bowl, whisk the egg whites until stiff and fold into the Stilton mixture.
Butter two ramekin dishes and sprinkle with breadcrumbs. Tap to remove excess breadcrumbs. Pour the mixture into the two ramekin dishes and cook for 8-10 minutes. Do not open the door before the cooking time is finished. Serve immediately.