Cheesy, Gooey Croques Monsieurs Recipe

Vicky Wasik

Why It Works

  • Slicing the bread thinly ensures that it doesn't overwhelm the filling.
  • Toasting tender bread on both sides gives the sandwich plenty of delicate crunch.
  • Cheesy Mornay sauce adds an extra layer (or two) of richness.

A good croque monsieur is all about nailing texture, bread-to-filling ratio, and the goo factor. This recipe, which calls for thin slices of toasted-on-all-sides bread, melted cheese, rich Mornay sauce, and Dijon mustard, is a case study in getting it right.

Recipe Facts

Active: 30 mins
Total: 30 mins
Serves: 4 servings

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  • 5 1/2 tablespoons (80g) unsalted butter, plus more if necessary, divided

  • 1 1/2 tablespoons (12g) all-purpose flour

  • 1 cup (235ml) milk

  • 6 ounces (170g) grated Gruyère, Comté, or Swiss cheese, plus more if desired, divided

  • Kosher salt and freshly ground black pepper

  • 8 (1/4 inch thick) slices soft bread, such as brioche or good-quality sandwich bread

  • 8 ounces (225g) good-quality thinly sliced ham (about 16 slices)

  • 4 teaspoons (20ml) Dijon mustard


  1. Preheat oven to 350°F. In a small saucepan, heat 1 1/2 tablespoons butter with flour over medium-high heat, until butter has melted and formed a paste with flour. Continue to cook, stirring, until raw flour scent is gone, about 1 minute. Whisk in milk until smooth and cook, whisking, until sauce comes to a simmer and begins to thicken slightly. Lower heat to low and cook, stirring, until sauce is thick enough to coat back of a wooden spoon, about 3 minutes. Whisk in 4 ounces cheese until smooth, moving saucepan on and off heat to keep it hot enough to melt cheese but not so hot that it bubbles rapidly. Season Mornay sauce with salt and pepper and keep warm.

  2. In a large cast iron skillet, working in batches, toast both sides of each slice of bread in remaining butter over medium heat until golden, about 2 minutes per side; swirl pan and rotate bread for even browning, and add more butter as necessary if pan dries out.

  3. Transfer bread to a work surface. Arrange ham on top of half the bread slices, then spread a generous layer of Mornay sauce on top of ham. Sprinkle with remaining grated cheese. Spread Dijon mustard on each of the remaining bread slices and close sandwiches. Spread additional Mornay sauce on top of each sandwich from edge to edge; sprinkle additional grated cheese on top, if desired.

  4. Transfer sandwiches to a baking sheet and heat in oven until sandwiches are warmed throughout and cheese is melted. Turn on broiler, then broil sandwiches on top rack until lightly browned on top, about 2 minutes. (Keep an eye on them, as some broilers are very powerful.) Serve right away.

Special equipment

Cast iron skillet, baking sheet

This Recipe Appears In

Nutrition Facts (per serving)
710 Calories
40g Fat
52g Carbs
36g Protein
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Nutrition Facts
Servings: 4
Amount per serving
Calories 710
% Daily Value*
Total Fat 40g 51%
Saturated Fat 22g 109%
Cholesterol 155mg 52%
Sodium 1544mg 67%
Total Carbohydrate 52g 19%
Dietary Fiber 3g 9%
Total Sugars 10g
Protein 36g
Vitamin C 0mg 1%
Calcium 629mg 48%
Iron 4mg 22%
Potassium 445mg 9%
*The % Daily Value (DV) tells you how much a nutrient in a food serving contributes to a daily diet. 2,000 calories a day is used for general nutrition advice.
(Nutrition information is calculated using an ingredient database and should be considered an estimate.)