Béchamel sauce

• 50 g/1¾ oz/3½ tbsp unsalted butter
• 50

Melt the butter in a non-stick saucepan over a low heat. Mix in the flour, using a wooden spoon, and slowly beat together for a few minutes. Remove the pan from the heat and whisk in the milk until blended.

Return to a medium heat, add the studded onion and bring just to the boil, stirring continuously. Turn the heat down to low and simmer for about 20 minutes, stirring occasionally to