A decadent, baked ham and cheese sandwich also know as the croque monsieur. This version is served open-faced and topped with creamy Gruyere cheese sauce. Perfect for holiday ham leftovers!
My husband just put me on this new thing. Maybe you've heard of it. I think they call it a budget? A grocery budget to be more specific. Apparently, this is well-known practice that households all over the world have been putting into action for some time now. News to me. Sure I was a little bummed at first, thinking of all the fancy cheeses I was going to be missing out on, but if we are looking on the bright side, I have been coming up with new and exciting ways to use up our leftovers.
Turns out, large pieces of protein can be a budgeting gals best friend. Take for instance, the holiday ham. It’s the protein that just keeps on giving. So generous, that ham, and I've found lots of great ways to knock out that little piggy without breaking the piggy bank. In fact, we broke it all the way down to the hock, then we threw it in some pinto beans and had a barbecue. Yes, I've found lots of great uses for my Honey-Glazed Baked Ham, but quite possibly one of my all-time favorites — le croque monsieur.
The first time I laid eyes on that handsome little number, it was love at first sight. I thought to myself, "What is that sandwich calling my name? The one with the luscious, cheesy situation baked on top? And also, how in the world does a sandwich know my name?" Okay, so that was a cheesy joke. Pun intended. Sorry. I’ll stop now. I know it sort of sounds like I wanted to date my lunch, but in truth, it was the beginning of a lifelong love affair.
It begins with a creamy mornay sauce, laden with perfect, stretchy Gruyere cheese. Now, I know what you thinking. What happened to that budget, Kelly? Yes, I know Gruyere is a bit of a high dollar cheese, but with all that money I saved on protein for the week, I was able to fit it in just fine. Look at me go!
Since this recipe began with leftover ham in mind, I felt an open-faced sandwich would be better suited for my thick-cut slices of protein. Two pieces of bread isn't really necessary for this level of decadence anyway. You want to make sure you use a good, high-quality, sturdy loaf of bread for this sandwich, such as a rustic French loaf or fresh, white sandwich bread from the bakery.
Lastly, we’ll slather on a little whole-grain mustard to cut through the richness and add some zing. Then, bodda-bing, bodda-boom: Brace yourselves for a love-at-first-bite affair with this dapper, French number.

A deliciously decadent sandwich featuring the classic Croque Monsieur served open-faced. Ready the knives and forks and dig in to big flavor!
- 4 ½ - ¾" slices white bakery bread
- 2-3 tablespoons room temperature unsalted butter for spreading + plus 3 tablespoons more, separated
- 3 tablespoons all-purpose flour
- 2 cups whole milk warmed
- 1 ½ cup freshly grated Gruyere cheese preferably Boars Head, separated
- ¼ cup freshly grated Parmesan cheese
- ½ teaspoon Kosher salt
- Generous pinch black pepper
- 10 ounces thick-cut ham torn or cut into large chunks
- ⅓ - ½ cup of whole-grain mustard
- 2 tablespoons minced chervil Italian flat-leafed parsley
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Preheat the oven to 425° and have ready a sheet pan lined with aluminum foil.
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Place a medium-sized skillet over medium-low heat. Spread a thin layer of butter evenly across both sides of each slice of bread. Place slices of bread on skillet, taking care not to overcrowd the pan, and allow to toast for 1 ½ - 2 minutes or until golden brown. Flip and repeat on other side. Set aside on a wire rack until ready to use.
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Add 3 tablespoons of butter to the same skillet and allow to melt. Immediately after butter has melted, sprinkle in flour and whisk until a paste has formed, 1-2 minutes. Add milk, one generous splash at a time, and whisk after each addition until the mixture begins to resemble a pudding-like texture. At this point, add the remaining milk in a small stream, whisking all the while. Increase the heat to medium-high, and allow the mixture to rapidly simmer 3-5 minutes, until slightly thickened, stirring often. Remove from the heat and stir in 1 cup of Gruyere cheese, Parmesan cheese, salt and pepper. Set aside until ready to use.
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Place each piece of toast across the sheet pan, spacing them at least 1" apart. Spread with a generous smear of whole-grain mustard. Divide ham amongst the toast. Place a generous dollop of cheese sauce on top of the ham and spread to cover. Divide the remaining Gruyere, and sprinkle across the sandwiches.
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Bake for 12 minutes, or until the cheese has melted and begins to bubble. Remove from the oven, sprinkle with chervil or parsley, if desired, serve and enjoy.
4 Servings