Preheat Convection to 220°C.
Preheat Metal Tray into oven for 15 minutes. Before removing tray from the oven, add 4 minutes to the timer. Remove tray, lightly oil the tray with a brush, crack eggs into diagonally opposite corners of the tray and return to oven. Press start to cook for 4 minutes. Remove and season with salt and pepper and set aside.
Place bread in one layer on the Grill Tray. Brush one side of each slice of bread with melted butter and place tray in the top shelf position in the oven. Cook on “Grill 1” for 4 minutes.
Whilst the bread is toasting, make the bechamel sauce. Melt butter in a small sauce pan. Add the flour and whisk for 30 seconds to make a paste. Gradually add the milk and whisk until smooth and slightly thickened. Add the cheese, whisk until melted. Turn off the heat and whisk in nutmeg and salt and pepper.
Remove from oven, turn two slices of bread over and spread the dijon mustard on those slices only. Top both slices with ham and cheese. Top the other slices that remain toasted side up with the bechamel sauce.
Place back into the oven, top shelf position and cook on “Grill 1” for 5 minutes.
Remove from the oven, assemble the sandwiches by placing the bechamel pieces of bread directly on top of the ham and cheese slices of bread. Top each sandwich with the prepared eggs.
Place the tray back in the oven, middle shelf position and cook on “Grill 1 for 1 minute.
Serve immediately with cornichons and dressed lettuce leaves.