Last night I attempted one of my French bistro sandwiches, the simply elegant Croque Monsieur. It’s a fancy sounding name for an elevated ham and cheese sandwich, but once you bite into one, you have to call it by name.
I cannot recommend exact quantities on this, as I feel you just assemble and make it look pretty. The quick bechamel I made was probably enough for two sandwiches, so I will go into a bit more detail with the sauce.
For the sandwich, I used two medium-thick slices of semolina bread, but any heart sliced bread or baguette will do – Italian, French, you could even go rye, though I prefer a milder tasting bread. I spread a thin layer of super grainy mustard and topped with ham. I then preheated my oven to 400 degrees and got started on the bechamel.
This was not a true bechamel. Instead a made a roux by melting two tablespoons butter and whisked in two tablespoons of flour. When the roux was cooked to a light blond color I added more grain mustard, a pinch of garlic powder (I would have preferred onion powder but I was out), a few dashes of nutmeg, salt and pepper. While whisking over low heat, I added 2/3 cup milk, added slightly more, thinning the sauce a bit more. You want the consistency to fall somewhere between mayo and gravy – thinner than mayo, but not so thin that it drips everywhere. I then added about two heaping tablespoons of Parmesan cheese and a teaspoon of Colman’s mustard powder.