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Closeup of a croque monsieur sandwich sliced in half and served on a plate with a gherkin pickle.

Croque Monsieur

Croque monsieur is a French sandwich made with ham, smothered in creamy béchamel and nutty Gruyère, and broiled till crispy and golden.
Course Main Dish
Cuisine French
Prep Time 10 minutes
Cook Time 20 minutes
Total Time 30 minutes
Servings 2 servings
Calories 1239kcal
Author Ann Otis


  • 1 ½ tablespoons butter
  • 3 tablespoons finely chopped yellow onion
  • 1 ½ tablespoons all-purpose flour
  • 1 cup milk
  • pinch ground nutmeg
  • salt and pepper
  • 4 slices sourdough bread
  • 2 tablespoons dijon mustard
  • 2 cups grated Gruyere cheese
  • 4 ounces sliced ham


  • Preheat the broiler on high. Line a large baking sheet with aluminum foil.
  • Make the béchamel: In a medium saucepan, melt the butter over medium heat. Add the onion and sauté until translucent, a minute or two. Add the flour and cook for one minute, whisking constantly. Add the milk and keep whisking to break up any lumps, until the sauce bubbles and thickens, 3-4 minutes. Remove from heat and whisk in nutmeg and a pinch of salt and pepper. Whisk in a half cup of the cheese.
  • On the prepared baking sheet, toast the bread slices under the broiler on both sides until golden. Keep a close eye on them as they will burn quickly!
  • On two of the bread slices, spread a tablespoon of Dijon mustard. Slather with a thick layer of béchamel sauce. Add sliced ham and a half cup of cheese. Top with the two remaining bread slices to make two sandwiches. Transfer the sandwiches to the aluminum-lined baking sheet. Top the two sandwiches with the remaining béchamel and cheese. 
  • Broil until the cheese is golden and bubbly, about 5 minutes.


Calories: 1239kcal | Carbohydrates: 85g | Protein: 71g | Fat: 67g | Saturated Fat: 36g | Cholesterol: 215mg | Sodium: 2071mg | Potassium: 636mg | Fiber: 3g | Sugar: 10g | Vitamin A: 1710IU | Vitamin C: 1.1mg | Calcium: 1537mg | Iron: 5.9mg