Croque Madame Recipe

Heat butter and make roux

In a small saucepan set over medium heat, melt 2 tablespoons unsalted butter. When the butter is foaming but not browned, whisk in 2 tablespoons all-purpose flour and cook, whisking constantly, for 1 to 2 minutes to form a blond roux (do not let it brown).

Add milk and season

Gradually whisk in 1 cup whole milk a little at a time so the mixture stays smooth. Continue whisking until the sauce thickens and comes to a gentle simmer, about 3 to 4 minutes. Reduce heat to low and simmer another 1 to 2 minutes until the béchamel coats the back of a spoon.

Finish béchamel

Remove from heat and stir in 1/2 teaspoon salt, 1/4 teaspoon freshly ground black pepper, and 1 teaspoon grated nutmeg. Taste and adjust seasoning. Keep warm; if it thickens too much as it cools, whisk in a tablespoon of warm milk to loosen before assembling sandwiches.

Prepare bread and fillings

Butter one side of each of the 8 slices of bread lightly (about 1 to 1 1/2 teaspoons per slice). On the unbuttered side of four slices, spread about 1/4 teaspoon Dijon mustard each. Top those four slices (mustard side up) with about 2 ounces ham per sandwich and a generous 1/2 cup of grated Gruyère each, leaving a small rim at the edge.

Assemble

Place the remaining four slices of bread on top of each prepared slice, buttered side up, to form four sandwiches.

Grill sandwiches

Heat a large skillet or griddle over medium heat. Place two sandwiches in the pan (or as many that fit without crowding) and cook 3 to 4 minutes per side until golden brown and the cheese inside has begun to melt, pressing gently with a spatula. If the bread is browning before the cheese melts, lower the heat and cover the pan briefly (30–60 seconds) to help the cheese melt. Transfer cooked sandwiches to a baking sheet and repeat with remaining sandwiches.

Top with béchamel and cheese

Preheat the broiler (or oven to 450°F/230°C on high rack). Spoon a generous 2 to 3 tablespoons of warm béchamel onto the top of each sandwich and spread to cover the surface. Sprinkle the reserved 1/4 cup grated Gruyère evenly over the béchamel (about 1 tablespoon per sandwich).

Broil to brown

Place the baking sheet under the broiler 3 to 6 inches from the heat. Broil for 1 to 3 minutes, watching carefully, until the béchamel bubbles and the cheese topping is golden and slightly browned. Remove from oven.

Fry eggs

While the sandwiches are under the broiler (or immediately after), heat 1 tablespoon butter or neutral oil in a small nonstick skillet over medium-low to medium heat. Crack 1 large egg per sandwich into the pan. Cook gently until the whites are set but yolks remain runny, about 2 to 3 minutes for sunny-side-up. If you prefer set yolks, baste the eggs with the hot fat or cover the pan for an extra 30–60 seconds. Season with about 1/8 teaspoon salt and a pinch of black pepper.

Top sandwiches

Place one fried egg on top of each broiled Croque Monsieur to turn it into a Croque Madame. Serve immediately so the yolk can be broken at the table and ooze into the sandwich.