Food EditionCookFrenchLunchAuthentic Croque Monsieur
20 minIntermediateServes 2
French · Lunch

Authentic Croque Monsieur

A Croque Monsieur is a grilled ham and cheese sandwich finished with a layer of bubbling Mornay sauce. The secret is the contrast between the crisp, butter-toasted bread and the thick, creamy béchamel crust that forms under the broiler.

Total time
20 min
Hands-on
20 min
Serves
2
Difficulty
Intermediate
Before you start

Balance is the goal

Use a sturdy sourdough or country loaf that won't turn into mush under the sauce. You want enough béchamel to coat the top, but not so much that the bread collapses.

  • Heavy-bottomed saucepan
  • Whisk
  • Cast iron skillet
  • Sheet pan
Ingredients

What goes in.

  • 2 tbspunsalted butter
  • 2 tbspall-purpose flour
  • 1 cupwhole milk, warmed
  • 1/2 cupGruyère cheese, grated
  • 4 slicesthick-cut sourdough bread
  • 4 sliceshigh-quality cooked ham
  • 1 tspDijon mustard
  • pinchnutmeg, freshly grated
The key technique

Mastering the Béchamel

Cook the butter and flour for two minutes until it smells like toasted almonds before adding milk. You are looking for a thick, velvety texture that coats the back of a spoon.

Step by step

The method.

  1. Make the base

    Melt butter in a small pan, whisk in flour, and cook until golden. Gradually pour in warm milk, whisking constantly to prevent lumps. Simmer until thickened, then remove from heat and stir in half the Gruyère, mustard, and nutmeg.

  2. Prepare the bread

    Lightly toast your bread slices in the skillet until they are golden brown on one side. This prevents the bread from absorbing too much moisture later.

  3. Assemble

    Spread a little Mornay sauce on the un-toasted side of two bread slices. Layer the ham and a generous sprinkle of remaining cheese, then top with the second bread slice, toasted side facing up.

  4. Glaze and broil

    Spread the remaining Mornay sauce over the top of the sandwiches, covering the edges completely. Place under a preheated broiler for 3 to 5 minutes until the top is bubbling and flecked with brown spots.

Variations

Other turns to take.

Croque Madame

Top the finished sandwich with a sunny-side-up egg fried in butter.

Tips & troubleshooting

When it doesn't go to plan.

Tip

Always grate your own cheese; pre-shredded bags contain anti-caking agents that stop the cheese from melting smoothly into the sauce.

Tip

Don't skip warming the milk; cold milk is the primary cause of lumpy sauce.

Tip

If the sauce gets too thick while you assemble, whisk in a tablespoon of milk to loosen it back up.

Questions

The ones that keep coming up.

Can I use Emmental instead of Gruyère?

Yes, it is a common substitute that melts similarly, though it lacks the sharp, nutty profile of Gruyère.

Should I remove the crusts?

Not necessary, but if your bread is very large, trimming them creates a cleaner look.

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