- ¼ cup (½ stick) unsalted butter
- ¼ cup all-purpose flour
- 1½ cups whole milk
- salt and pepper
- 1/4 tsp dijon mustard
- Dash ground nutmeg
- 8 thin slices white sandwich bread
- 5 oz. good quality ham (about 8 slices)
- 6 oz. Gruyère or Emmental cheese, grated (about 2½ cups)
- 1/4 cup fresh grated Parmesan cheese
For the Béchamel:
- Melt butter in a medium saucepan over medium heat. Whisk in flour and cook, stirring constantly, for about 3 minutes. Gradually add milk, stirring well until the mixture is smooth. Cook, stirring, until sauce is thickened. Season with a little bit of salt and pepper. Remove from heat and whisk in mustard and nutmeg.
- Preheat oven to 425° F. Spread bread slices with a layer of béchamel, spreading it all the way to the edges. Place 4 slices of bread, béchamel side up, on a parchment-lined baking sheet. Top each with a piece of ham, a handful of gruyere, and a sprinkle of parmesan cheese. Place remaining slices of bread on top, béchamel side up, then top with remaining gruyere and parmesan cheese.
- Bake at 425 degrees F for about 5-6 minutes, until cheese is melted, and then turn the oven to broil and broil until the cheese on top is golden, 2-4 minutes.