Method

Mornay Sauce 

Set a medium size pot over medium heat. Melt the butter, then add the flour and cook while stirring for 2 minutes to cook out the flour. Slowly add the milk – whisking continuously to prevent lumps. Add the Dijon mustard and whisk to combine. Gently bring to a simmer to thicken, then remove from the heat and add the cheese. Whisk to combine and melt the cheese, then season to taste. The sauce should be the consistency of a thick mayonnaise.

Sandwich

Butter one side of 4 slices of bread. Set the oven grill on full and toast one side only of the slices. Remove from the oven and set aside. Reduce the oven temperature to 180 ºC.

To assemble, lay two toasted pieces of bread onto a work surface, toasted side face down. Spread a little sauce on the bread, then top with about a teaspoon of wholegrain mustard. Add a little cheese to each slice then top with a slice or 2 of ham. Add a little more cheese, then top with an untoasted middle slice of bread. Top that slice with more cheese, more ham and more cheese. Close up the sandwich with the toasted top facing up. Do this for both sandwiches. Place onto a baking paper-lined tray. Top each sandwich with a good dollop of Mornay sauce, then add a little more cheese to the top. Bake for 10-15 minutes to heat through, then turn on the grill to brown the top ensuring that you keep an eye on it. Once bubbling and golden, remove from the oven, allow to cool slightly then slice and serve with fries.