Croque Madame

Name: Croque Madame
Prep time: 25 min
Cook time: 10 min
Total time: 35 min
Cuisine: France
Ingredients: 25 g (2 tbsp) unsalted butter; 25 g (3 tbsp) all-purpose flour; 300 ml (1¼ cups) whole milk, warm; 1 tsp Dijon mustard; 1 pinch nutmeg; 2 g (⅓ tsp) fine sea salt; 60 g (⅔ cup) Gruyère, grated; 8 slices white sandwich bread or pain de mie, 1.5 cm thick; 30 g (2 tbsp) unsalted butter, softened; 2 tsp Dijon mustard; 8 slices good cooked ham, about 200 g; 100 g (1 cup) Gruyère, grated; 4 large eggs; 1 tbsp neutral oil or butter, for frying the eggs

Ham and Gruyère toastie under bubbling Mornay, topped with an egg

Makes: 4 sandwiches
Hands-on: 25 min
Total: 35 min
Level: Some skill

The Paris café classic: a ham and cheese sandwich crowned with cheese sauce and baked until bubbling and browned. Add a fried egg and it becomes a croque madame.

Ingredients

Mornay sauce

25 gunsalted butter (2 tbsp)
25 gall-purpose flour (3 tbsp)
300 mlwhole milk (1¼ cups)warm
1 tspDijon mustard
1 pinchnutmeg
2 gfine sea salt (⅓ tsp)
60 gGruyère (⅔ cup)grated

Sandwiches

8 sliceswhite sandwich bread or pain de mie1.5 cm thick
30 gunsalted butter (2 tbsp)softened
2 tspDijon mustard
8 slicesgood cooked hamabout 200 g
100 gGruyère (1 cup)grated
4large eggs
1 tbspneutral oil or butterfor frying the eggs

Allergens: gluten, milk, egg, mustard
Origin: France (Paris)

Method

Heat the oven to 200°C (400°F) with the grill element on if your oven has one. Line a baking sheet with baking paper.
Make the Mornay: melt the butter in a saucepan over medium heat, stir in the flour and cook for 1 minute. Gradually whisk in the warm milk and simmer, whisking, for 5 minutes until thick. 5 min
Off the heat, stir in the mustard, nutmeg, salt and the 60 g Gruyère. This is a thick Mornay; for the method in detail, see Béchamel.
Butter one side of each bread slice. Place four slices buttered side down on the baking sheet. Spread with mustard, and top each with two slices of ham and a quarter of the grated Gruyère.
Cover with the remaining bread, buttered side up.
Bake for 5 minutes until lightly toasted, then flip the sandwiches. 5 min
Spread the Mornay thickly over the tops of the sandwiches, covering them to the edges, and bake 8–10 minutes until bubbling and browned in patches. 9 min
Meanwhile, fry the eggs sunny-side up (see Fried Eggs).
Top each sandwich with a fried egg and serve at once with a knife and fork.

Why it works

Toasting the sandwich first crisps the bread and starts melting the cheese inside, so the Mornay doesn't turn the bread soggy. The sauce's milk proteins and cheese brown under high heat through the Maillard reaction, giving the blistered golden top. Mustard in both the sandwich and the sauce cuts through the richness.

Common mistakes

Thin Mornay: it runs off and soaks the bread. Simmer until it thickly coats a spoon.
Skipping the first toast: soggy sandwich.

Variations

Croque monsieur: Leave off the egg.

Make ahead and storage

The Mornay keeps 2 days in the fridge; reheat gently before spreading.

Notes

Fan oven: 180°C (350°F). It is a hot, baked, knife-and-fork sandwich; for cold, open Nordic sandwiches on rye, see Smørbrød: Three Open Sandwiches.