Collect together your equipment (see Recipe Notes below) and ingredients.

Preheat oven to Fan Oven 180°C /200°C/400°F/Gas 6

First make the bechamel sauce: in a medium saucepan melt the butter, add the flour and cook for a couple of minutes stirring continuously with a wooden spoon or balloon whisk.

Pour in the milk all at once, mix vigorously with a balloon whisk until evenly incorporated and there are no lumps. Bring to the boil – as it heats, the sauce will thicken.

Now I prefer to use my wooden spoon or spatula again. Reduce the temperature and simmer gently for 3 – 4 minutes, stirring continuously.

Add the remaining ingredients, the mustard, salt, pepper, nutmeg and cheese, and cook stirring, until thoroughly mixed and the cheese has melted.

Now bring the sandwich together: lightly toast the bread.

Spread ¼ of the bechamel on one slice of bread and a further ¼ on the second piece of bread.

Top with a slice of ham and spread the ham with some Dijon mustard.

Sprinkle ¼ of the cheese on one slice and a further ¼ on the second piece.

Top each with a second slice of lightly toasted bread.

Spread both equally with the remaining bechamel cheese and scatter over the rest of the cheese.

Bake in the centre of a pre-heated oven for 20 – 25 minutes until the cheese has melted, is a light golden brown and bubbling hot.

Serve sprinkled with some chopped chives and prepare to eat this heavenly sandwich!