Spread mustard on bread. Layer 4 bread slices with Swiss cheese, ham, and cheese again. Place remaining bread slices on top.
In a shallow dish, whisk together eggs, milk, salt, pepper, and nutmeg. Dip each sandwich in the egg mixture, turning to coat well.
In a large skillet, melt butter over medium-low heat. When butter is foamy, add the sandwiches, and cook, turning once, until golden brown on both sides, 6 to 8 minutes total. Serve immediately, dusted with confectioners' sugar.
Is it truly a Monte Cristo without the jam and turkey? While this one tastes good, its even better with the jam (our favorites are strawberry or raspberry) and the turkey. That's how I've had them in restaurants too.
This sandwich was absolutely delicious! I really loved the combination of all the different flavors. I did stray from the original recipe by using deli ham AND deli turkey. In addition to dusting the sandwich with powdered sugar, we also dipped them in raspberry jam. I had gotten that idea from reading other recipes for Monte Cristo sandwiches on the internet, and it definitely improved it. I loved the contrast between the sweet sugar and jam with the tart/tangy mustard. DE-lish!