Baked Croque Monsieur Casserole Recipe

croque monsieur casserole topped with sauce

Baked Croque Monsieur Casserole Recipe

Course: Breakfast

Cuisine: American, French

Keyword: baked croque monsieur casserole, croque monsieur casserole recipe, gruyère casserole, ham and cheese breakfast casserole, overnight croque monsieur casserole

Prep Time: 25

Cook Time: 35

Total Time: 1

Servings:

Calories: 375kcal

Author: Jessica Formicola

This Croque Monsieur Casserole layers ham, Gruyère, Dijon, and a silky béchamel for a make-ahead brunch bake with a golden, broiled top.

Print Recipe

Equipment

Ingredients

5-6 cups sourdough, , brioche or country loaf , 1-2 days old and cut into 2-inch cubes
1 ½ cups cubed ham*
10 tablespoons salted butter , divided
1 leek , whites only, cut into half moons
6 eggs
1 ¼ cups half-and-half
2 tablespoons Dijon mustard
1 ½ teaspoons coarse kosher salt , divided
1 teaspoon ground black pepper , divided
3 cups Swiss or Gruyere cheese , grated and divided
2 tablespoons Parmesan cheese , finely grated
4 tablespoons flour
2 cups whole milk
1/4 teaspoon grated nutmeg
1 tablespoon chives , chopped

Instructions

Preheat the oven to 375°F and grease or spray a 9x13 baking dish. Place the cubed 5-6 cups sourdough, , brioche or country loaf and 1 ½ cups cubed ham* into the baking dish, toss lightly. Set aside.
Melt 1 tablespoon of the butter in a small saucepan over medium heat. Add the cut 1 leek, sautéing until soft. Evenly divide them over the bread and ham.
Melt 5 tablespoons of the butter in the microwave. In a medium mixing bowl, combine the 5 tablespoons of the melted butter, 6 eggs, 1 ¼ cups half-and-half, 2 tablespoons Dijon mustard, 1 teaspoon of the Kosher salt and ½ teaspoon of the black pepper.
Pour half of the custard mixture over the bread, tossing and pressing down gently to get the custard to absorb into the bread. Pour the remaining over top and repeat the pressing and tossing. Add the shredded 3 cups Swiss or Gruyere cheese, tossing again so the cheese is evenly distributed.
Cover with aluminum foil and bake for 25 minutes. Remove the foil and continue to bake for another 15 minutes or until the internal temperature reaches 160°F using a digital thermometer. Remove and top with the grated 2 tablespoons Parmesan cheese, returning to the oven under broil for 1-2 minutes until the top is golden brown and edges are crunchy. Allow the casserole to rest for 5 minutes, bringing it up to 165°F.
Meanwhile (while the casserole is baking), melt the remaining 4 tablespoons of butter, whisking with the 4 tablespoons flour until it forms a roux. Allow it to build brown slightly before whisking in the 2 cups whole milk. When the sauce has thickened and is smooth, remove from the heat and whisk in the 1/4 teaspoon grated nutmeg, remaining 1 ½ teaspoons coarse kosher salt and 1 teaspoon ground black pepper.
To serve, the sauce can be spooned over the whole casserole or served on the side in a gravy boat. Sprinkle with chopped 1 tablespoon chives.
If you've tried this casserole, come back and let us know how it was in the comments or star ratings.

Notes

*Deli ham or leftover ham can also be used. Black forest is the pick for me if I'm grabbing deli ham.

Make Ahead Options:

Make the Casserole The Night Before to Soak- Many readers find this one to be the winner and actually love that the custard has more time to soak into the bread. Prepare the casserole through step #4, then cover and chill over night. Give it a quick stir the next morning and let is sit out while the oven preheats to take the chill off.
Make the Béchamel The Night Before- The creamy sauce can also be made the night before, but will need to be reheated and likely re-seasoned. Do not reheat it in the microwave, instead put it in a saucepan over low heat and add 1-2 tablespoons additional milk to thin it out. Taste it and see it it needs more salt, likely it will only need a pinch.
Cook The Casserole The Night Before- You can also prepare and bake the casserole the night before and then reheat it the next day. Prepare it through topping it with parmesan cheese, bake at 350°F for 20-25 minutes, checking the internal temperature gets to 165°F and then proceed with the broiler and parmesan cheese.

Leftovers: Leftovers can be covered and stored for up to 5 days in the fridge. To reheat, do this in small pieces in the oven at 300°F until warm. Avoid the microwave, it will just make it gummy.

Freezing: This is a freezer friendly casserole without the béchamel sauce- make that fresh when you serve it. See our instructions for how to freeze a casserole.

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