Cheesy, Gooey Croques Monsieurs

Ham, cheese, rich sauce, and golden-toasted bread make this French classic perfect. Put an egg on it, and you have the equally delicious croque madame.

Top down view of two croque monsieur sandwiches on a cutting board.

Serious Eats / Vicky Wasik

Why It Works

  • Slicing the bread thinly ensures that it doesn't overwhelm the filling.
  • Toasting tender bread on both sides gives the sandwich plenty of delicate crunch.
  • Cheesy Mornay sauce adds an extra layer (or two) of richness.

I've heard a tale that the croque monsieur was discovered by French workmen who placed their lunch pails next to a radiator. When they sat down to eat, their ham and cheese sandwiches had melted from the heat, and the rest is history. Of all the world's ridiculous food-creation myths, that has to be one of the worst. Are we really meant to believe that it took an accident like that to make the culinary geniuses of France realize how damned good a hot ham and cheese sandwich would be?

Then again, stranger things have happened. Perhaps the strangest, in this context anyway, is that bad croques monsieurs exist. I can't even begin to fathom how someone could mess up a hot ham and cheese sandwich, and yet some people manage to find a way. Just a few months ago, in fact, I went out to brunch with some friends. My arm was in a cast, which made eating with both fork and knife nearly impossible. I figured the croque was a good choice, though. But the greasy monstrosity that hit the table was tough as wood and thick as Larousse. I couldn't pick it up with one hand, I couldn't cut it, and I could hardly bite through it. I ended up jabbing my fork right into its center and lifting the whole thing up like one of those cartoon porterhouse steaks. It was, by any measure, a bad croque monsieur.

There are three things that I think are essential to a good croque:

  • A good ratio of bread to filling.
  • A delicately crispy crunch that quickly gives way to tenderness. No thick, impenetrable rustic crusts, thanks.
  • Melty goo.

Oh, make that four things: butteriness. A croque should definitely be buttery.

A 3-photo collage of slicing bread thinly, toasting the bread in butter on both sides, and putting ham on half of the bread.

Serious Eats / Vicky Wasik

So let's start with the ratio of bread to filling. It's important that the amount of bread doesn't overshadow the ham and cheese inside. This means thin slices of bread—not more than three-eighths of an inch thick, though, if you can cut them even thinner, a quarter inch thick is ideal. Any thicker and you'd have to start bumping up the amount of ham and cheese in the center to balance it out—and, while that may sound like a good thing, I warn you that it quickly becomes grotesque. This sandwich, when done right, is hella rich, and therefore is best kept to a more restrained size.

Next, there's the texture: A good croque monsieur is both crisp and tender. The key here is choosing the right bread. I like brioche for my croque because it's both soft and buttery, but any high-quality white sandwich bread is good here. The secret to its crispness is in the toasting. I treat a croque just like all the grilled cheese sandwiches we make here at Serious Eats, which means toasting both sides of each slice of bread in butter. This gives it double the crispness, which is incredibly important for a sandwich with such moist fillings—otherwise, the inside surface of the bread gets steamed and mushy.

Technically, a croque should be classified as a melt, but whatever, melts are really just grilled cheese sandwiches with bonus food added.

The last consideration is the goo factor. The melted cheese, of course, provides a lot of it, but I like to take it one step further and add Mornay sauce. That may sound all fancy and complicated, but it's really just béchamel (a.k.a. white sauce) with cheese melted into it. It's essentially the same thing as the sauce used in a classic cheddar mac and cheese, except that I reach for a good Swiss cheese, Gruyère, or Comté for a croque. The Mornay adds a silky and creamy layer to go alongside all that stretchy melted cheese.

That's basically it: Toast the bread in butter on both sides, layer it with a couple of slices of good ham and freshly grated cheese, and then slather on the Mornay. A bit of Dijon mustard adds just enough vinegary punch to balance all that richness.

For a final touch, I spread more Mornay on top of the closed sandwiches, although you could just as easily sprinkle grated cheese all over each sandwich instead. Or do both...on second thought, you really should do both.

Then throw the sandwiches in the oven to melt it all together. If you want to brown the tops, a quick trip under the broiler does the trick, though that's totally optional.

Make It a Croque Madame

Two croque madame sandwiches with sunny side eggs on top. One is split in half with a golden yolk running out.

Serious Eats / Vicky Wasik

Here's the best part: While I was working on this recipe, a bird flew by and accidentally dropped an egg right on top of one of my test sandwiches. Not knowing what else to do, I cooked it, then ate the sandwich. I decided to call it the croque "madame," and, lemme tell you, it's even better than the monsieur.*

See the Notes after the recipe to see how to cook the egg for a croque madame.

* This, ladies and gentlemen, is how spurious creation myths are born.


How to Make Sunny-Side Up Fried Eggs

April 2016

Recipe Facts

Active: 30 mins
Total: 30 mins
Serves: 4 servings

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  • 5 1/2 tablespoons (80g) unsalted butter, plus more if necessary, divided

  • 1 1/2 tablespoons (12g) all-purpose flour

  • 1 cup (235ml) milk

  • 6 ounces (170g) grated Gruyère, Comté, or Swiss cheese, plus more if desired, divided

  • Kosher salt and freshly ground black pepper

  • 8 (1/4 inch thick) slices soft bread, such as brioche or good-quality sandwich bread

  • 8 ounces (225g) good-quality thinly sliced ham (about 16 slices)

  • 4 teaspoons (20ml) Dijon mustard


  1. Preheat oven to 350°F (180°C). In a small saucepan, heat 1 1/2 tablespoons butter with flour over medium-high heat, until butter has melted and formed a paste with flour. Continue to cook, stirring, until raw flour scent is gone, about 1 minute. Whisk in milk until smooth and cook, whisking, until sauce comes to a simmer and begins to thicken slightly. Lower heat to low and cook, stirring, until sauce is thick enough to coat the back of a wooden spoon, about 3 minutes. Whisk in 4 ounces cheese (reserving the rest for inside the sandwiches) until smooth, moving saucepan on and off heat to keep it hot enough to melt cheese but not so hot that it bubbles rapidly. Season Mornay sauce with salt and pepper and keep warm.

  2. In a large cast iron skillet, working in batches, toast both sides of each slice of bread in remaining butter over medium heat until golden, about 2 minutes per side; swirl pan and rotate bread for even browning, and add more butter as necessary if pan dries out.

  3. Transfer bread to a work surface. Arrange ham on top of half the bread slices, then spread a generous layer of Mornay sauce on top of ham. Sprinkle with remaining grated cheese. Spread Dijon mustard on each of the remaining bread slices and close sandwiches. Spread additional Mornay sauce on top of each sandwich from edge to edge; sprinkle additional grated cheese on top, if desired.

    A 4-photo collage of adding Mornay sauce and shredded cheese in croque monsieurs, closing the sandwich and adding another layer of Mornay sauce.

    Serious Eats / Vicky Wasik

  4. Transfer sandwiches to a baking sheet and heat in oven until sandwiches are warmed throughout and cheese is melted. Turn on broiler, then broil sandwiches on top rack until lightly browned on top, about 2 minutes. (Keep an eye on them, as some broilers are very powerful.) Serve right away.

Special Equipment

Cast iron skillet, baking sheet


To make a Croque Monsieur into a Croque Madame, simply top each sandwich with a fried egg with a runny yolk.

Nutrition Facts (per serving)
710 Calories
40g Fat
52g Carbs
36g Protein
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Nutrition Facts
Servings: 4
Amount per serving
Calories 710
% Daily Value*
Total Fat 40g 51%
Saturated Fat 22g 109%
Cholesterol 155mg 52%
Sodium 1544mg 67%
Total Carbohydrate 52g 19%
Dietary Fiber 3g 9%
Total Sugars 10g
Protein 36g
Vitamin C 0mg 1%
Calcium 629mg 48%
Iron 4mg 22%
Potassium 445mg 9%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)