Curtis Stone’s Croque Madame

To make the Mornay sauce, in a medium heavy saucepan, melt the butter over medium-high heat. Stir in the flour and cook, stirring frequently, for about 2 minutes, or until the butter and flour are well-blended and beginning to smell toasted. Gradually stir in half of the milk and bring the mixture to a boil, stirring constantly to prevent lumps. Stir in the remaining milk and bring back to a boil, stirring constantly. Simmer, stirring, for 3 minutes, or until the sauce has thickened. Remove from the heat and stir in the Gruyère until melted. Stir in the Dijon mustard and nutmeg, and season with salt and pepper. Cover to keep the sauce warm.

Make-Ahead: The Mornay sauce can be made up to 2 days ahead, cooled, covered, and refrigerated. Rewarm in a heavy saucepan over medium heat, stirring, for about 3 minutes and adding more milk to thin the sauce to the desired consistency, if necessary.

Preheat the broiler. Line a heavy baking sheet with foil.

In a large heavy skillet, heat 1/2 tablespoon of the butter over medium heat until bubbly. Add 2 pieces of bread to the pan and toast for about 3 minutes per side, or until golden brown. Transfer the bread to the prepared baking sheet. Repeat with the remaining 2 pieces of bread, using another 1/2 tablespoon of the butter.

Divide half of the Gruyère among the toasts. Top each with 2 slices of ham then scatter the remaining cheese on top of the ham. Broil the toasts for about 3 minutes, or until the cheese is browned and bubbling. Transfer the sandwiches to plates.

Meanwhile, in a large heavy nonstick skillet, melt 1/2 tablespoon of the butter over medium-high heat. Crack 2 eggs into the skillet and fry for about 3 minutes, or until the egg whites have set and the yolks have thickened but not set. Place 1 sunny-side-up egg on each sandwich.

Repeat with the remaining 2 eggs, using the remaining 1/2 tablespoon butter for each egg.

Pour the warm Mornay sauce evenly over the toasts and serve immediately.

*PAIN DE MIE - This French bread, called a Pullman loaf in the States, is a rectangular loaf of white sandwich bread with a fine-grained texture. Pain de mie toasts up well but other high-quality white sandwich bread, or even sliced French bread, can be substituted here.