Croque-Monsieur: A Perfect Back To School Lunch Recipe

In France, the croque-monsieur sandwich is as much a staple of school children's lunches as the PB&J is in America. I grew up with them, and they are still the ultimate comfort food for me.
The girls are going back to school today and I wanted to share with them one of the fondest culinary memories of my childhood. When I was in middle school, I would come home early on Wednesdays. Since I didn't eat lunch at school, I would always make myself a croque-monsieur.
Croque-monsieur is super easy to make. All you need is a few ingredients such as sliced white bread, emmental cheese and ham (I used smoked turkey). To make it fancier, I bind all the ingredients together with a Mornay sauce, which is basically a béchamel with cheese. I use béchamel a lot; it's really just a white sauce made of flour, butter and milk.
Ingredients
Yields: 4 servings
8 slices bread4 tablespoons unsalted butter, at room temperature
2 tablespoons all-purpose flour
1-1/4 cups whole milk, warm
2 teaspoons coarse-grain mustard
1/4 cup shredded cheese (I used emmental)
1/4 cup parmesan cheese, freshly grated
1 pinch nutmeg, freshly grated
1/4 teaspoon salt
1 pinch white pepper, freshly ground
4 slices smoked turkey
8 slices emmental cheese
Directions
For the bread: Slightly toast the bread for a few seconds without browning it at all. This will prevent the bread from getting soggy after you add the Mornay sauce. It will stay perfect all the way to lunch time if you prepare it in the morning.
For the Mornay sauce: In a saucepan, melt 2 tablespoons of butter over medium-low heat. Add the flour. Whisk for approximately 2 minutes. The flour should absorb the butter instantly and form a paste. Add the warm milk in 3 stages. Increase the heat while constantly stirring for about 5 minutes. Lower the heat to low. Add mustard and nutmeg. Mix well, then add the shredded cheese and grated parmesan. Season with salt and pepper. Cover the sauce with the remaining 1/2 tablespoon of butter to keep it from forming a skin. Let the sauce cool completely.
Assembly time: Spread butter on one side of the bread and about a tablespoon (or less) of Mornay sauce on the other side. Place the slice of bread; butter side down. Layer the sandwich with a slice of emmental cheese, a slice of smoked turkey and another slice of cheese. Close the sandwich with a second piece of bread. Brush a hot griddle pan with a little butter. Place the sandwich onto the griddle. Cook until you get grill marks (about 2-3 minutes on each side) over medium heat. Remove from the pan. Let the croque-monsieur cool a bit and cut the sandwich in quarters.
Serve with some chips and some crudités (crunchy vegetables), such as a cucumber salad. Your kids will ask for more!
Enjoy!
Tips
To make a Mornay sauce, I always use all the ingredients at the same temperature, so make sure to heat the milk in the microwave for 30 seconds (or in a saucepan), so it's warm. If you get lumpy pieces in the sauce, don't hesitate to use a handheld blender.
If you have Mornay sauce left-over, don't discard it. Just thin it with a little milk and use it as a sauce for your pasta.
I used smoked turkey, but any cold meat is fine.
You can use any kind of cheese that is stringy when melted, such as Gruyère, Comté or Beaufort.
My favorite tool for grating hard cheese is the Microplane fine grater.