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Croque Monsieur

Croque Monsieur or Madame on Buttery Croissant

Grilled ham and Swiss cheese on buttery croissants smothered in a creamy cheese sauce. For the croque-madame, the sandwich is topped with a fried egg. Accompanied with avocado slices.
Course Main Course, sandwich
Prep Time 15 minutes
Cook Time 10 minutes
Total Time 25 minutes
Servings 4
Author Christina Lakey


For the Sauce:

  • 2 tablespoons unsalted butter
  • 2 tablespoons all-purpose flour
  • 1 1/2 cups milk
  • 1 teaspoon salt
  • 1/2 teaspoon black pepper
  • Pinch of nutmeg
  • 1/2 cup Gruyere cheese grated
  • 1/2 cup Parmesan cheese grated

For the Sandwich:

  • 4 buttery croissants
  • Dijon mustard
  • 8 slices of your favorite ham sliced
  • 2-3 cups Gruyere cheese grated


  • 4 eggs if making croque-madame
  • 2 avocados pitted, halved, and thinly sliced


  1. Preheat the oven to 350 F.

For the Sauce:

  1. In a small saucepan, melt the better over medium heat. Add the flour and stir together to create a roux.
  2. Pour in the milk in small additions. Allow the sauce to slightly thicken between each addition, whisking constantly to prevent lumps. Once all milk is added, continue to whisk and cook until thickened, about 2 minutes. Turn heat to low.
  3. Add Gruyere and Parmesan cheese and stir until melted. Take off heat and add salt, pepper, and nutmeg to taste. Set aside.
  4. Note: Sauce will thicken more as it cools down. This is fine. It is good to have a very thick sauce as it stays on top of the sandwiches better during cooking.

For the Sandwiches:

  1. Slice the croissants and place face up on a baking sheet. Place in oven and toast for 30 seconds. Turn over and toast for 30 seconds. Remove.
  2. Spread a thin layer of Dijon mustard on bottom half of each croissant. Add two slices of ham, then the grated Gruyere. Close sandwich with top half of croissant. Generously slather each sandwich top with cheese sauce. Top off with any remaining Gruyere.
  3. Place in oven and bake 3-5 minutes, just long enough to heat through and melt the cheese.
  4. Turn oven to broil, and broil an additional 3-5 minutes until cheese sauce starts bubbling and croissants start to lightly brown.

For Croque-Madame:

  1. Heat a small frying pan over medium heat. Generously butter pan. Crack an egg and cover with lid. Cook sunny-side up until whites are firm, but yolks are still soft. Slide egg onto top of sandwich. Repeat for each egg and sandwich.
  2. Serve hot with avocado slices on the side.

Recipe Notes

Quick tip:The key to this sandwich is to lightly toast the croissant so that it does not get soggy when adding the sauce, but to not overcook which will dry out the croissant. If ever in doubt, less time is better!
Dress it Down (Classic Style):
1. Stick with the Croque-Monsieur (without egg) and lose the avocado garnishment.
2. Use normal sandwich bread instead of a croissant. Depending on the soggy factor of the bread you use, you may need to toast for a different amount of time before assembling the sandwich.
Change it Up (Substitutions): For the Gruyere, you may substitute normal Swiss cheese. The flavor will be about the same, but the Gruyere does produce a smoother texture. I've done it with Swiss and it still tastes great!