Cup of Yum
1. Preheat oven to 400°F.

Make the Béchamel Sauce

Cup of Yum
1. In a small saucepan, melt butter on medium/low heat until it just starts to bubble.
2. Add the flour, stirring until smooth for about 2 minutes.
3. Slowly add the milk, whisking continuously. Cook until it's thickened and then remove from heat.
4. Add salt, pepper, and nutmeg and then slowly stir in the parmesan and about 1/4 cup of the Gruyère and stir to melt all of the cheese.

Assemble the Sandwiches

1. Line a baking sheet with parchment paper. Add sliced bread and add them to the oven, cook for a couple of minutes on each side to toast. Or use a toaster oven - but you will still need parchment paper lined baking sheets.
2. Add bread slices to parchment lined baking sheet and brush the toasted slices with mustard, to taste (we love a lot of mustard!). Add the ham slices and about 1 cup of the remaining Gruyère cheese. Top with the other toasted bread slices.
3. Spoon on the béchamel sauce to the tops of the sandwiches. Sprinkle with the remaining Gruyère cheese.
4. Bake in the oven on the medium rack for 5 minutes, then turn on the broiler and broil for an additional 3 to 5 minutes, until the cheese topping is bubbly and lightly browned. You can also grill the sandwiches in a skillet on the stove top and then just finish them in oven to melt the cheese.
5. Slice in half and serve immediately.