1. Preheat the grill to medium-high, line the tray with foil and put the butter in a pan over a medium-low heat to melt it.

• Brush one side of each slice of bread liberally with melted butter and put under the grill butter-side uppermost until golden and crisp, then set aside.

2. Stir the flour into the remaining butter to make a paste, cook for a minute, then gradually whisk in the milk, a little at a time, until smooth.

• Simmer for a few minutes, until thickened, then take off the heat and stir in 30g cheese until melted. Grate in a little nutmeg, stir and season lightly.

3. Spread the untoasted sides of the bread with mustard, then put the ham on top,

• followed by the cheese, and pop under the grill for a couple of minutes until the cheese has melted.

4. Top with the rest of the bread, with the toasted side uppermost, and push down, then put the sandwiches on to the grill tray and top with bechamel sauce.

• Grill for about 5 minutes, until golden and bubbling, and serve immediately.

= BECHAMEL =