Croque Monsieur

For the béchamel: Melt the butter in a large saucepan over medium heat. Add the nutmeg and toast for a minute or so. Add the flour and whisk into the melted butter until smooth. Cook, whisking, until the flour turns a light golden color, 6 to 7 minutes.

Increase the heat to medium-high and slowly stream in the milk, whisking, until thickened. Bring the mixture to a gentle simmer, then reduce the heat to medium-low and continue simmering until the flour no longer tastes gritty, 10 to 20 minutes.

Add the Gruyère, Dijon mustard and Worcestershire sauce and stir until melted. Season with salt and black pepper. (As the mixture sits, it can thicken, so you can whisk in more milk if needed.)

For the sandwich: Preheat the oven to 400 degrees F.

On one slice of bread, spread the Dijon mustard. On the other, spread about 1 tablespoon béchamel. Add 3 slices Gruyère on one side, followed by the ham, then 1/2 cup of the grated Gruyère. Place the other piece of bread over the grated Gruyère.

In a large nonstick skillet, melt the butter over medium heat. Season the butter with salt and pepper. When the butter just begins to sizzle, add the sandwich. Place a heavy-bottomed cast-iron pan on top of the sandwich to serve as a press and cook until golden brown, 3 to 4 minutes. Flip and cook for 3 minutes more. (No need to use the press on the second side.)

Top with 1/4 to 1/2 cup béchamel, followed by the remaining cup grated Gruyère, allowing some of the cheese to fall into the skillet to create a frico-like crust around the bottom edge of the sandwich. Top with a couple tablespoons grated Parmesan and place in the oven until the cheese is melted and begins to brown on top, 5 to 10 minutes.