📝 About This Recipe
Born in the bustling brasseries of early 20th-century Paris, the Croque Monsieur is the quintessential French comfort food, elevated far beyond a simple ham and cheese toastie. This decadent masterpiece features thick slices of buttery brioche layered with nutty Gruyère and artisanal ham, all smothered in a luxurious, nutmeg-scented Mornay sauce. Toasted until golden and bubbling, it offers a sublime contrast between the crisp, 'crunchy' exterior (the 'croque') and the molten, creamy heart.
🥗 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, traditional French style)
- 1 pinch Nutmeg (freshly grated is best)
- 1 pinch Kosher salt and black pepper (to taste)
For the Sandwich Assembly
- 4 slices Brioche or Pain de Mie (cut 1/2 inch thick)
- 2 tablespoons Unsalted butter (softened, for spreading)
- 2 teaspoons Dijon mustard (for the interior spread)
- 4 slices Jambon de Paris (or high-quality unsmoked deli ham)
- 1.5 cups Gruyère cheese (freshly grated, divided)
- 1 tablespoon Parmigiano-Reggiano (finely grated for the topping)
👨🍳 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-low heat, melt 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 pour in the warm milk a little at a time, whisking constantly to prevent lumps. Continue cooking and whisking until the sauce thickens enough to coat the back of a spoon.
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4
Remove the saucepan from the heat. Stir in 1/4 cup of grated Gruyère, 1 teaspoon of Dijon mustard, nutmeg, salt, and 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 the broiler for 1 minute per side until just barely golden.
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6
Spread a thin layer of softened butter on one side of all four slices of bread. Flip two slices over and spread a thin layer of Dijon mustard on the non-buttered side.
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7
Place two slices of ham on each of the mustard-slathered bread pieces, folding the ham so it fits perfectly within the edges of the bread.
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8
Sprinkle about 1/4 cup of grated Gruyère over the ham on each sandwich, then top with the remaining bread slices, buttered-side up.
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9
Heat a non-stick skillet over medium heat. Place the sandwiches in the pan and toast for 2-3 minutes per side until the bread is golden brown and the cheese inside begins to melt.
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10
Transfer the toasted sandwiches to your prepared baking sheet. Generously spoon the Mornay sauce over the top of each sandwich, spreading it right to the edges.
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11
Sprinkle the remaining 1 cup of Gruyère and the tablespoon of Parmigiano-Reggiano evenly over the sauce-covered tops.
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12
Place the baking sheet in the oven for 5 minutes, then turn on the broiler for 2-3 minutes until the cheese is bubbling and has developed beautiful brown spots.
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13
Remove from the oven and let rest for 2 minutes—this allows the sauce to set slightly so it doesn't slide off when you bite into it.
💡 Chef's Tips
Always grate your own Gruyère; pre-shredded cheese is coated in potato starch which prevents that silky, professional melt. Use a high-quality, slightly thick bread like brioche or levain; thin sandwich bread will collapse under the weight of the Mornay sauce. If your Mornay sauce gets too thick while cooling, simply whisk in a splash of warm milk to loosen it before spreading. For a 'Croque Madame' variation, simply top the finished sandwich with a sunny-side-up fried egg. Don't skip the nutmeg—it is the secret ingredient that gives the French white sauce its characteristic depth.
🍽️ Serving Suggestions
A simple green salad with a sharp vinaigrette to cut through the richness of the cheese. Crispy cornichons (French tart pickles) on the side for a vinegary crunch. A chilled glass of dry white wine, such as a Sauvignon Blanc or a Chablis. A light tomato bisque for dipping during the colder months. Freshly cracked black pepper and a sprinkle of chives over the top for a pop of color.