If you haven’t realized it yet, my love language is a block of cheese.
Shocker? Not at all. I talk about cheese all the time.
The struggle is real, but so is the bliss. Give me burnt, bubbly, golden bread covered in cheese and I’m an easy person to please.
At first glance this might look like a tray of golden blobs. But it’s actually crisped baguette topped with crunchy ham and a generous smothering of gruyère cheese sauce.
And mustard. The grainier, the better. I may have an embarrassing mustard collection—truffle mustard, beet mustard, and more—because condiments are a serious hobby for me. Trader Joe’s gift sets? I buy them for myself. I will eat a spoonful of mustard on the daily. No shame.
This recipe hooked me years ago for one main reason: mustard. Yes, the cheese is essential, but the mustard is the flavor that pulls everything together. Every ingredient matters here—rich gruyère, a touch of nutmeg, crisp ham, and that tangy grainy dijon.
If you remember when I made a croque madame, this is basically that idea in bite-size form—just without the egg. Turning a beloved sandwich into little crostini is dangerous because mini portions let you eat more. We all know that math.
These crostini are an excellent holiday appetizer or party snack. You can prep most of it ahead: crisp the ham and slice the baguette, even mix the grated cheeses in advance. I recommend making the cheese sauce last so it stays smooth—reheat gently on low if you need to transport it, then spoon it over the assembled bites and bake until bubbly.
Mini crostini = more bites. Need I say more?
Croque Monsieur Crostini
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Ingredients
Cheese Sauce
- 1/2 tablespoon unsalted butter
- 1/2 tablespoon flour
- 2/3 cup half and half
- 1 cup freshly grated gruyere cheese
- pinch salt, pepper + nutmeg
Croque Monsieur
- 6 ounces deli ham
- 1 large baguette, sliced (15 to 20 pieces)
- 1/2 cup grainy dijon mustard
- 1/2 cup freshly grated gruyere cheese
- 1/4 cup freshly grated parmesan cheese
- fresh herbs for sprinkling parsley, basil, sage
Instructions
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Note: using crispy ham adds great texture but is optional.
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Preheat the oven to 425°F (220°C). Line a baking sheet with parchment paper.
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Heat a large nonstick skillet over medium-high. Add the ham in batches and cook, turning, until crispy on all sides. Transfer to a plate and tear into pieces once cooled.
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For the cheese sauce: warm a small saucepan over medium. Add butter, then whisk in flour and cook until lightly golden, about 1–2 minutes. Gradually add half and half, stirring until slightly thickened. Reduce heat to low and stir in gruyère until melted. Season with salt, pepper and a pinch of nutmeg.
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In a bowl, combine the grated gruyère and parmesan for topping.
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Assemble: spread each baguette slice with grainy dijon mustard, sprinkle a little of the grated cheese, top with a piece of crispy ham, spoon over a generous amount of cheese sauce and finish with more grated cheese. Repeat for all slices.
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Bake for about 15 minutes, until golden and bubbly. If desired, broil for a minute at the end to deepen the color.
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Serve immediately, garnished with fresh herbs.
Did you make this recipe?
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I appreciate you so much!
And yes, I definitely ate all the stray cheese off the baking sheet. #ihavenoidea