Method

• 1.
  Melt the butter in a saucepan over low heat, add the flour and cook for 1-2 minutes without letting the mixture brown.
• 2.
  Add the milk and continue to cook over low heat for about 4-5 minutes or until thick. Add half the grated cheese, stirring to combine. Set aside to cool.

• 3.
  Spread 2 slices of the bread with Dijon mustard, place the ham and remaining cheese on top and cover with another bread slice. Place on a baking tray and grill the sandwiches under a hot grill on one side.
• 4.
  Remove sandwiches from the grill, turn over and spread the ungrilled side with the cheese sauce, return to the grill and cook until golden and bubbling.