Croque-Monsieur

Some sandwiches are easy to pick up and eat on the go. The classic French croque-monsieur is not. Slathered with a creamy bechamel sauce (one of the mother sauces made by thickening milk with a roux), the hot sandwich is a sit-down meal. The bechamel makes a croque-monsieur rather decadent, so it’s great to serve at a fancy holiday brunch or for a leisurely lunch. Have leftover Easter ham? This sandwich is the perfect way to use it.

What is a croque-monsieur?

This classic French sandwich has existed for over a century, first mentioned in print in the 1890s and popularized by a Parisian bistro in the 1910s. It’s decadent and delicious, made with soft sliced bread that’s spread with piquant Dijon mustard, layered with ham, and topped off with white sauce and Gruyere cheese. It’s broiled so the top gets bubbly and melted—like grilled cheese on steroids.

The sandwich is the base for the croque-madame, which has the same combination of ingredients with an egg perched on top. The more modern Monte Cristo—which, despite its name, is an American invention—involves dipping a ham and cheese sandwich in batter and pan-frying the custard-sopped result, making it a cross between a croque-monsieur and French toast.

Croque-Monsieur Ingredients

• Butter: Because the ham and cheese in this recipe are salty, and you’ll add a measured amount of salt to the bechamel sauce, this is a great time to use unsalted butter. The butter, whisked in a pan with flour, forms the base of the sauce.
• Flour: Needed more for its thickening power than for its flavor, all-purpose flour is the perfect pantry staple to use when you’re learning how to make bechamel.
• Milk: A croque-monsieur isn’t low-fat fare, so lean into it by using whole milk to make the white sauce. If you don’t have a carton of the full-fat version, 2% will do the trick.
• Seasonings: A hint of nutmeg gives bechamel sauce a gorgeous, fragrant note, which is complemented by a zing from cayenne and black pepper. Adding salt brings out the other flavors.
• Dijon mustard: Not all mustards are created equal, and Dijon has a particularly sharp flavor that makes it an ideal match for fatty, salty ingredients. If you don’t have store-bought or homemade Dijon, brown mustard makes a better substitute than yellow mustard.
• Brioche bread: The classic bread for croque-monsieur is a tender French loaf called pain de mie. This bread is soft and a touch sweet. Our recipe calls for easier-to-find brioche.
• Ham: Use the best-quality ham possible in this sandwich, whether it’s leftover from a holiday meal or sliced from the grocery store deli.
• Gruyere cheese: A variety of cheese that originated in Switzerland, Gruyere is an excellent melting cheese. If you can’t find it, try substituting Emmenthaler, Appenzeller or Jarlsberg. American-style Swiss cheese doesn’t have the same depth of flavor.

Directions

Step 1: Make the bechamel sauce

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Preheat your oven to 425°F. Heat the butter in a small saucepan over medium heat. Once the butter is melted, whisk in the flour and cook until it’s lightly browned and bubbly, two to three minutes. Slowly whisk in the milk and cook until it’s thickened, four to five minutes, stirring frequently. Season with salt, pepper, nutmeg and cayenne.

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Remove the bechamel sauce from heat and set it aside.

Editor’s Tip: Roux is the combo of fat and flour used to thicken sauces, soups and stews. It’s a crucial ingredient in other recipes like shrimp gumbo and classic turkey gravy.

Step 2: Build the sandwiches

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Spread Dijon mustard on one side of each piece of bread.

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Spread 1 tablespoon of bechamel sauce on four of the bread slices. Place them on a foil-lined baking sheet.

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Top each bechamel-covered bread piece with three slices of ham and 1/4 cup of shredded Gruyere.

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Place the remaining brioche slices on top. Spread the rest of the bechamel sauce on top of the sandwiches.

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Sprinkle the sandwiches with the remaining cheese.

Step 3: Cook the sandwiches

Bake the croque-monsieurs for six to seven minutes or until the cheese is melted. Turn the oven to broil, and broil them for one to two minutes, watching carefully through the oven window, until the tops are lightly golden brown.

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Croque-Monsieur Variations

• Try it with turkey: Instead of ham, try making croque-monsieurs with another type of sliced meat, such as turkey or chicken breast.
• Make it Italian: Skip the bechamel sauce and replace it with a smear of ricotta or mascarpone mixed with honey and chili flakes, and add arugula to the filling. As a final touch, use fontina cheese in place of the Gruyere.
• Try a New England twist: Put apple slices inside the sandwich and use shredded cheddar cheese on top.

How to Store Croque-Monsieur

Due to the creamy sauce and gooey melted cheese, croque-monsieur is best when freshly made. If you have extras, wrap them tightly in storage wrap and then foil, stack them in a container with a tight-fitting lid, and store them in the fridge. Leftover croque-monsieurs will last up to four days in the refrigerator.

How do you reheat a croque-monsieur?

Preheat the oven to 350°. Place the leftover sandwiches on a sheet pan, and bake them for about 10 minutes, until the bread has re-crisped and the cheese is melted. If desired, turn on the broiler for a minute or two until the cheese bubbles.

Can you make croque-monsieur sandwiches ahead of time?

These sandwiches are most enjoyable when just made, but bechamel sauce holds up well in the fridge and can be made up to four days in advance. Once you have that prepped, the sandwiches practically make themselves.

Croque-Monsieur Tips

What’s the best bread for a croque-monsieur?

Although the traditional bread for the croque-monsieur is dense, white sandwich bread, some people like to make these with slices from a crusty, country-style loaf. Avoid using American-style super-soft white or wheat bread, as they’re too delicate to stand up to the white sauce.

What should you serve with a croque-monsieur?

A croque-monsieur is a decadent sandwich, so pair it up with a nice light vegetable side to make an elegant meal. Dishes like stir-fried green beans, spinach salad with goat cheese and beets or Thomas Keller zucchini would be perfect.