Adapted from Bar Boulud
Time: 40 minutes
FOR THE BéCHAMEL SAUCE:
3 tablespoons unsalted butter
1/4 cup all-purpose flour
3 cups whole milk
Pinch of freshly grated nutmeg
Salt and freshly ground white pepper
For the sandwiches:
2 tablespoons unsalted butter, melted
8 slices high-quality Pullman loaf bread, sliced 1/3- to 1/2-inch thick
12 ounces thickly sliced Jambon de Paris (high-quality wet-cured ham)
10 ounces Gruyère cheese, coarsely grated.
1. For the béchamel: In a small saucepan over low heat, melt butter and whisk in the flour until blended but not colored. Gradually whisk in the milk and cook, stirring constantly, until thickened, about 10 minutes. Season to taste with nutmeg, salt and pepper. Set aside. (May be made up to 24 hours ahead of time and stored, refrigerated, with a layer of plastic wrap placed directly on surface of sauce; gently reheat before serving.)
2. For the sandwiches: Preheat oven to 400 degrees. Line a sheet pan with parchment paper and brush with melted butter. On a work surface, place bread slices in a single layer and spread each one evenly to the edges with béchamel; all the béchamel may not be needed. Divide ham among four of the slices, trimming it if necessary so it is within 1/4 inch of edges. Top all eight slices with equal amounts of cheese, spreading it evenly to within 1/4 inch of edges.
3. Place four bread slices with béchamel and cheese, cheese side up, on top of slices layered with ham. Transfer sandwiches, cheese side up, onto sheet pan. Bake until grated cheese topping is melted and golden brown, 10 to 15 minutes. Serve immediately.
Yield: 4 servings.