Literally translated, a Croque Monsieur means “Crunchy Mister” or “Crispy Mister.” Truth be told, no one actually knows how the sandwich got its name or when it was first conceived. Essentially, this a ham and cheese melt that you could get at any local diner, but scaled up by melting the cheese on the outside of the bread as well as the inside.
This version updates the classic hot ham and cheese by topping the entire sandwich with mornay sauce (béchamel with cheese) and sauteed mushrooms, and baking the entire thing in the oven. Mornay sauce is a white sauce with parmesan cheese mixed into it. It’s delicious on pasta as well, so be sure to make extra for later.
Mornay Sauce Ingredients (makes 2 cups)
- 1 1/2 tbsp butter
- 1 1/2 tbsp all purpose flour
- 1 1/2 c whole milk
- 2 bay leaf
- 1/2 c Parmesan cheese
- Pinch of nutmeg
Croque Monsieur Ingredients (makes 4 sandwiches)
- 1/2 lb ham slices
- 1/4 lb swiss cheese, sliced
- 1/4 lb gruyere cheese
- 6 oz crimini (baby bella) mushrooms, sliced
- 3 tbsp butter at room temperature
- 2 tbsp Parmesan cheese
- 1 loaf crusty bread
1. Start by heating the butter in a small saucepan over medium heat (5 on the dial). Add the flour to the butter and continously whisk until the mixture becomes a pale golden brown. In cooking, this is called a roux (pronounced like Winne the Poo’s young kangaroo friend).
2. Mix the milk into the roux and whisk until combined. Add the bay leaf and turn the heat up to medium high. Whisk until the mixture begins to thicken. Do not boil or you will have a milky mess and will cry over spilled milk. Turn the heat down to simmer (a 2 on the dial) for 10 minutes.
3. Preheat the oven to 450 degrees. Meanwhile, heat some oil in a saute pan over medium high heat (7 on the dial). Add the mushrooms to the oil and saute until the mushrooms have released most of their juices and reduced in size. Set aside to cool.
4. Slice the bread into 1/3″ pieces. Butter the bread on one side and toast in a pan. You can also toast this much bread under the broiler. I have issues with the broiler and tend to burn things quickly, but if you have skill, this is a much quicker way.
5. The sauce should be done by now. A skin may have formed on the top. If this has happened, just whisk the skin into the mixture. Turn the heat off and mix the nutmeg and parmesan cheese into the sauce. Set aside.
6. Build your sandwich. Start with the bread, toasted side down. Top with ham, then swiss cheese, and then top with a second piece of bread, toasted side up. Press down on the sandwich to compress. Top the bread with enough mornay sauce to make you happy, then add the mushroom on top. Top the whole thing with the gruyere cheese.
Note: I used an inferior deli sliced gruyere here; a small block of gruyere grated would work better. You’ll can see in the picture below that the deli gruyere keeps it’s shape, while grated will melt together and ooze all over your bread.
7. Bake the whole sandwich in the oven for 10 minutes or until the cheeses have melted and the top begins to bubble and brown.
8. Serve with sweet gherkins and whole grain mustard.