Classic Croque Monsieur

Instructions

1. Prepare the béchamel sauce
   Melt 30g of butter in a saucepan over medium heat. Add the flour and stir continuously for 2-3 minutes until the mixture turns slightly golden. Gradually whisk in the warm milk, ensuring no lumps form. Cook, stirring constantly, until the sauce thickens, about 5 minutes. Remove from heat and stir in the nutmeg, Dijon mustard, salt, and pepper. Allow to cool slightly.
2. Toast the bread
   Preheat your oven to 200°C (400°F). Lightly butter one side of each bread slice. Place the slices butter-side down on a baking sheet and toast in the oven until lightly golden, about 5 minutes. Remove from the oven but keep the oven on.
3. Assemble the sandwiches
   Spread a thin layer of béchamel sauce on the unbuttered side of 4 bread slices. Top each with 2 slices of ham and about 30g of grated Gruyère. Place the remaining bread slices on top, with the buttered side facing outward.
4. Apply the topping
   Spread a generous layer of béchamel sauce on top of each sandwich. Sprinkle with the remaining Gruyère and the Parmesan cheese. Season with a little black pepper.
5. Bake to perfection
   Bake the sandwiches in the preheated oven until the cheese is bubbly and golden brown, about 10-15 minutes. If needed, broil for the last 1-2 minutes to get a perfect golden top. Watch carefully to prevent burning.
6. Serve hot
   Remove from the oven and let rest for 2 minutes. Serve immediately while hot and crispy, with a side salad of mixed greens dressed with a light vinaigrette if desired.