Croque Madame Recipe

Warm milk

Heat the milk in a small saucepan or in the microwave until warm but not boiling (about 30–45 seconds). Set aside.

In a medium saucepan over medium heat, melt 2 tablespoons unsalted butter. Whisk in 2 tablespoons flour and cook, whisking constantly, for 1–2 minutes to form a blond roux — do not let it brown.

Slowly whisk the warm milk into the roux in a thin stream to avoid lumps. Continue to whisk and bring to a gentle simmer; cook until thickened, about 3–5 minutes.

Whisk in 1 teaspoon Dijon mustard, 1 teaspoon salt, 1/2 teaspoon freshly ground black pepper, and 1 teaspoon freshly grated nutmeg. Remove from heat.

Stir in 1 cup grated Gruyère until melted and smooth. If the sauce is too thick, thin with 1–2 tablespoons milk to a spreadable consistency. Keep warm while assembling sandwiches.

Preheat the oven to 425°F (220°C). Line a baking sheet with parchment or lightly grease it.

Butter one side of each bread slice with the softened butter. Place 4 slices, buttered side down, on the prepared baking sheet (these will be the sandwich bottoms).

Lightly spread about 1/4 teaspoon Dijon mustard onto the unbuttered side of each bottom slice.

Top each bottom slice with 2 slices of ham, pressing slightly so they lie flat, then top with about 1/2 cup Gruyère (sliced or grated) per sandwich.

Place the remaining 4 slices of bread on top, buttered side up, to form 4 sandwiches.

Spoon or brush a generous layer (about 2–3 tablespoons) of the warm béchamel over the top of each sandwich, then sprinkle an additional tablespoon or two of grated Gruyère on top of the sauce.

Place the baking sheet in the preheated oven and bake until the cheese topping is bubbly and golden, about 8–10 minutes. For a deeper golden crust, transfer the pan to broil for 1–2 minutes, watching carefully to avoid burning.

While the sandwiches bake, heat 1 tablespoon butter or neutral oil in a large nonstick skillet over medium heat until foaming.

Crack the eggs into the skillet (work in two batches if necessary). Cook until the whites are set but the yolks remain runny, about 2–3 minutes for sunny-side up. If you prefer the tops set, cover the pan briefly or baste the whites with hot butter.

Season each fried egg with a pinch of salt and a grind of black pepper. Keep warm until sandwiches are ready.

Remove the baked sandwiches from the oven. Carefully transfer each sandwich to a plate.

Place one fried egg on top of each sandwich. Spoon a little extra béchamel from the pan over the egg if desired and sprinkle with the remaining 1/2 cup grated Gruyère.

Garnish with chopped chives or parsley if using. Serve immediately while hot so the yolk runs into the sandwich when cut.