The croque monsieur was invented in Paris in the early 1900s and has been a popular indulgence ever since. If you ever find yourself in Paris, you will see some version of a croque monsieur at almost every bakery or bistro.
WHAT IS A CROQUE MONSIEUR?
The traditional ingredients for a croque monsieur include sliced ham and Gruyère cheese between two pieces of white sandwich bread (called “pain de mie” in France). The sandwich is then topped with a béchamel sauce (a classic white sauce), more cheese, and then baked in the oven until the cheese is bubbly and golden brown.
I stray slightly from the classic by adding a little bit of cheese to my béchamel sauce (which technically then becomes a Mornay sauce — a béchamel sauce with cheese added). I also like the added flavor of Parmesan cheese.
MAKE IT YOUR OWN!
The amount of ham and cheese added to your croque monsieur doesn’t make too much of a difference — it really comes down to personal preference! You can also try different cheeses you may have on hand, like a sharp white cheddar or Gouda.
WHAT IS A CROQUE MADAME?
A popular variation of the croque monsieur is the “croque madame”. It is made in the exact same way as a croque monsieur, but with the addition of a fried egg on top.
PREPARING THE MORNAY SAUCE (CHEESY WHITE SAUCE)
Preheat your oven to 400℉.
Add the milk to a small saucepan set over medium heat until it heats up just before the boiling point. Turn off the heat and set aside.
In a second, larger sauce pan set over medium-low heat, heat the butter until it is fully melted and begins to foam. Add in the flour and cook it for 1 to 2 minutes, stirring constantly with a wire whisk.
Next, slowly pour in the hot milk into the flour/butter mixture and continue to whisk constantly until it forms a smooth sauce. Continue to cook the sauce, while whisking constantly for 3 to 5 minutes, until it has thickened.
Stir in the salt, pepper, nutmeg, Gruyère, and Parmesan cheese and cook until the sauce begins to bubble. Taste for seasonings. Remove from the heat and set aside.
ASSEMBLING AND BAKING THE SANDWICHES
Meanwhile, place the slices of bread (in a single layer) on a baking sheet and bake them for 5 minutes. After five minutes, turn them over and bake them for another 3 minutes, or until nicely crisp and toasted.
Remove the slices from the oven and place them on a cooling wrack while assembling the sandwiches. This will help prevent them from getting soggy!
Spread half of the toasted bread with Dijon mustard, followed by the sliced ham, followed by ⅓ cup of the grated Gruyère cheese. Top each sandwich with the remaining slices of toast and move them back onto your lined baking sheet.
Spoon some of the cheesy white sauce over the top of each sandwich, being careful to spread the sauce right to the edges of the bread — this will help prevent the edges from burning in the oven! Top the sandwiches with the remaining Gruyère and Parmesan cheese.
Pro tip: Depending on the size of your sandwiches, you may have some of the cheese sauce leftover. You can use it for dipping, or allow it cool it completely and store it in the fridge or freezer for future use!
Place them back in the oven for 8 minutes. After 8 minutes, turn on the broiler and broil them for another 3 to 5 minutes, or until the cheese on top is bubbly and golden brown. Serve warm.
Croque Monsieur
Ingredients
For the Mornay Sauce (Cheesy White Sauce)
- 1 ½ cups whole milk
- 3 Tbsp unsalted butter
- 3 Tbsp all-purpose flour
- ½ tsp kosher salt (I use Diamond Crystal)
- ¼ tsp ground black pepper (or ground white pepper)
- ⅛ tsp ground nutmeg
- ⅓ cup Gruyère cheese, freshly grated
- ⅓ cup Parmesan cheese, freshly grated
For the Sandwiches
- 8 slices good-quality white sandwich bread (or sourdough)
- Dijon mustard
- 240 g (about ½ lb) sliced ham
- 2 ½ cups Gruyère cheese, freshly grated
- ½ cup Parmesan cheese, freshly grated
Instructions
- Preheat oven to 400℉.
Preparing the Mornay Sauce (Cheesy White Sauce)
- In a small saucepan set over medium heat, heat milk until just before it begins to boil. Turn off heat and set saucepan aside.1 ½ cups whole milk
- In a (separate) large sauce pan over medium-low heat, heat butter until it is fully melted and begins to foam.3 Tbsp unsalted butter
- Add in flour. Whisking constantly, cook butter and flour together for 1 to 2 minutes.3 Tbsp all-purpose flour
- Slowly pour hot milk into the flour/butter mixture. Whisking constantly, cook mixture until it forms a smooth sauce and then for another 3 to 5 minutes until it has thickened.
- Stir in salt, pepper, nutmeg, Gruyère, and Parmesan cheese. Cook until the sauce begins to bubble. Taste for seasonings. Remove sauce from heat and set aside.½ tsp kosher salt¼ tsp ground black pepper (or ground white pepper)⅛ tsp ground nutmeg⅓ cup Gruyère cheese, freshly grated⅓ cup Parmesan cheese, freshly grated
Assembling and Baking the Sandwiches
- Meanwhile, place slices of bread (in a single layer) on a baking sheet lined with parchment paper. Bake for 5 minutes. Flip over and bake until nicely crisp and toasted (about 3 minutes).
- Remove toasted bread from the oven and set them on a cooling rack while assembling the sandwiches. (This will help prevent them from getting soggy.)
- On half of the toasted bread, spread Dijon mustard and top with sliced ham, followed by about ⅓ cup of the grated Gruyère cheese. Stack second slice of toast on top. Set each sandwich back onto the lined baking sheet.
- Spoon about ¼ cup of the cheesy white Mornay sauce over the top of each sandwich, spreading the sauce right to the edges of the top slice of toast. (This will help prevent the edges from burning in the oven!) Top sandwiches with remaining grated Gruyère and Parmesan cheeses.Pro tip: Depending on the size of your bread/sandwiches, there may be some Mornay sauce leftover, which is great for dipping! Otherwise, allow any extra to cool completely and store (in an airtight container) in the refrigerator or freezer for future use. (Mornay sauce can also be used for other great recipes, like a quick, homemade mac and cheese!)
- Bake for 8 minutes, then broil until cheese on top is bubbly and golden brown (about 3 to 5 minutes more). Serve warm.
Notes
- Bread suggestion: Traditionally, croque monsieur is made with white sandwich bread, called “pain de mie” in France. I like to use a slightly thicker slice of bread for this recipe, which I find helps prevent the sandwiches from getting too soggy.
- Make it your own! The specific quantities of ham and cheese in this recipe are just a guideline, and you can add as much (or as little) as you wish. You can also swap out the cheeses with whatever you’d like — just be mindful that different cheeses contain different amounts of salt, so don’t forget to taste as you go!
- Try a croque madame: The counterpart to the croque monsieur is called the “croque madame“. It is exactly the same, except topped with a fried egg before serving!
