📝 About This Recipe
Born in the bustling brasseries of early 20th-century Paris, the Croque Monsieur is the definitive evolution of the grilled cheese sandwich. This decadent masterpiece features layers of nutty Gruyère cheese and premium jambon de Paris, all enveloped in a silky, nutmeg-infused Mornay sauce. Toasted to golden perfection, it offers a sublime contrast between the crunchy, buttery sourdough and the rich, molten interior that defines French comfort food.
🥗 Ingredients
For the Mornay Sauce
- 2 tablespoons Unsalted butter (high quality)
- 2 tablespoons All-purpose flour
- 1 cup Whole milk (warmed slightly)
- 1/4 cup Gruyère cheese (finely grated)
- 1 teaspoon Dijon mustard (smooth style)
- 1/8 teaspoon Nutmeg (freshly grated)
- 1/4 teaspoon Fine sea salt (to taste)
- 1/8 teaspoon White pepper (ground)
For the Sandwich
- 4 slices Sourdough or Pain de Mie (thick-cut, about 3/4 inch)
- 2 tablespoons Unsalted butter (softened for spreading)
- 4 slices Jambon de Paris (or high-quality deli ham)
- 1.5 cups Gruyère cheese (grated, divided use)
- 2 tablespoons Parmesan cheese (freshly grated for the crust)
- 1 pinch Herbes de Provence (optional garnish)
👨🍳 Instructions
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1
Preheat your oven to 400°F (200°C) and line a small baking sheet with parchment paper.
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2
In a small saucepan over medium heat, melt the 2 tablespoons of butter. Once foaming, whisk in the flour and cook for 1-2 minutes to remove the raw flour taste, ensuring it doesn't brown.
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3
Slowly drizzle in the warm milk while whisking constantly to prevent lumps. Continue to cook, whisking frequently, until the sauce thickens enough to coat the back of a spoon.
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4
Remove the pan from heat. Stir in 1/4 cup of grated Gruyère, Dijon mustard, nutmeg, salt, and white pepper until the cheese is melted and the sauce is glossy.
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5
Lightly toast the bread slices in a toaster or under a broiler for 1-2 minutes per side until just barely crisp.
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6
Spread a thin layer of softened butter on one side of each bread slice, then flip them over.
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7
Spread a generous tablespoon of the Mornay sauce onto the unbuttered side of all four slices of bread.
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8
On two of the slices, layer two slices of ham (folded to fit) and a handful of grated Gruyère cheese.
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9
Close the sandwiches with the remaining two bread slices, Mornay-side down, so the buttered side faces up.
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10
Heat a cast-iron skillet over medium heat. Sear the sandwiches for 2 minutes per side until the bread is golden brown and crispy.
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11
Place the seared sandwiches onto your prepared baking sheet. Spoon the remaining Mornay sauce generously over the top of each sandwich.
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12
Sprinkle the remaining Gruyère and the Parmesan cheese over the sauce-covered tops.
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13
Bake in the oven for 5 minutes, then turn on the broiler for 2-3 minutes until the cheese topping is bubbly and develops deep brown spots (the 'leopard' look).
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14
Remove from the oven, sprinkle with a pinch of Herbes de Provence if desired, and let rest for 2 minutes before serving.
💡 Chef's Tips
Always grate your own cheese; pre-shredded cheese is coated in potato starch which prevents the Mornay sauce from becoming perfectly smooth. If the Mornay sauce gets too thick while sitting, whisk in a tablespoon of warm milk to loosen it before spreading. For an authentic touch, use Jambon de Paris, which is a slow-cooked, lightly salted ham that isn't overly sweet or smoky. Don't skip the nutmeg—it is the secret ingredient that provides the characteristic French flavor profile to the white sauce. Ensure your bread is sturdy; a flimsy white bread will fall apart under the weight of the sauce and cheese.
🍽️ Serving Suggestions
Serve with a simple side of mixed greens tossed in a sharp lemon-shallot vinaigrette to cut through the richness. A crisp, dry white wine like a Sancerre or a chilled Chardonnay pairs beautifully with the melted Gruyère. Accompany with a few cornichons (French tart pickles) for a traditional brasserie presentation. For a 'Croque Madame' variation, top the finished sandwich with a sunny-side-up fried egg. A light tomato bisque makes for a wonderful dipping companion on a cold day.