Croque Monsieur Casserole

Croque Monsieur sandwiches are my absolute favorite sandwich in the world. The luscious béchamel, ham and toasty bread is just pure heaven to me. Usually it is easy to just make two for Marc and me, but this week I wanted to make them for a lunch crowd. Enter this wonderful croque monsieur casserole! I made it almost like a french toast casserole with an egg mixture to bind everything. All of the yummy elements of the sandwich were there with the béchamel, ham and gruyere layered over the bread base.

Said bread base was a bunch of lovely, buttery croissants instead of the usual brioche. I thought they would be more flaky and crispy in the casserole.
I also whipped up a simple small batch of my favorite French mother sauce in the world, béchamel. It is decadent and rich and so good. It’s a huge part of any croque monsieur sandwich so I had to of obviously use it in this casserole version.
After that, I quickly whisked together my egg mixture. The flavor highlight was definitely the herbs de provence. It always takes the sandwich to the next level and it did the same for the casserole. This egg mixture beautifully held the casserole all together.
Once I assembled the croque monsieur casserole with lots of yummy gruyere on top, I let it sit for an hour so that the croissants could soak up all of the flavors. This could also be made the night before for an easy make ahead meal!

After it sat, I just baked the casserole for about 45 minutes. It became gloriously bubbly and the gruyere became slightly brown and crisp on top. This really made such a fantastic meal for a crowd. Best of all, I think it works anytime of day from breakfast through dinner. Hope you all enjoy it too! xo

Croque Monsieur Casserole
Croque Monsieur Casserole
3.45 from 20 votes
Croque Monsieur Casserole
Croque Monsieur Casserole
Prep Time
15 mins
Cook Time
45 mins
Resting Time
1 hr
Total Time
1 hr

This croque monsieur casserole has all of the elements of the amazing sandwich in a yummy croissant based casserole that works any time of day!

Course: Main Course
Keyword: Croque Monsieur, Croque Monsieur Breakfast Casserole
Servings: 6
Calories: 636 kcal
Author: Jeanie and Lulu's Kitchen
  • 3 tablespoons butter
  • 3 tablespoons all-purpose flour
  • 1 1/2 cups milk
  • 1 pinch salt
  • 8 whole croissants diced into small chunks
  • 1/4 pound deli ham diced small
  • 5 whole eggs
  • 3/4 cup milk
  • 1 pinch salt
  • 1 pinch black pepper
  • 1 teaspoon herbs de provence
  • 1/2 teaspoon garlic powder
  • 4 ounces freshly grated gruyere cheese
  1. First, make the béchamel sauce. Get a small sauce pan on the stove and start to melt the butter in it over medium high heat. Whisk in the flour until you have a golden brown, thick roux. Slowly pour in the milk while you keep whisking. Add in the salt, then let the sauce gently simmer on medium heat for 5-10 minutes, whisking it occasionally, until it is thick and luscious. While it cooks, start to assemble the casserole. Get out a 9 x 13 baking pan and spray it well with cooking spray. 

  2. Lay out the chopped croissants in an even layer on the bottom, followed by the ham. Spread the finished béchamel on top of that in a thin layer. Then whisk the eggs, milk, salt, pepper, herbs de provence and garlic powder together in a bowl. Pour it over everything and gently press down the casserole so that the egg mixture really soaks into it. Finally, sprinkle the gruyere evenly over the top. Cover it and put it in the refrigerator to develop flavor for at least an hour or up to overnight. When you are ready to bake it, pre-heat the oven to 350. Bake the casserole uncovered for about 45 minutes, until it is set and the gruyere is almost brown and crispy. Cut it into 6 large squares or even 12 small squares. Serve and enjoy!

Nutrition Facts
Croque Monsieur Casserole
Amount Per Serving (1 square)
Calories 636 Calories from Fat 340
% Daily Value*
Fat 37.8g58%
Saturated Fat 20.5g128%
Cholesterol 251mg84%
Sodium 1160mg50%
Potassium 285mg8%
Carbohydrates 49.6g17%
Fiber 2.7g11%
Sugar 14.6g16%
Protein 24.2g48%
Calcium 280mg28%
Iron 2.9mg16%
* Percent Daily Values are based on a 2000 calorie diet.
Croque Monsieur Casserole
Croque Monsieur Casserole


10 thoughts on “Croque Monsieur Casserole”

Comments are closed.