Croque Monsieur Casserole (Printable)

Buttery bread layered with ham, Gruyère, and béchamel sauce baked until golden and bubbling for French comfort.

# What you'll need:

→ Bread & Dairy

01 - 12 slices white sandwich bread, crusts removed
02 - 3 tablespoons unsalted butter, softened
03 - 1.5 cups Gruyère cheese, grated
04 - 1 cup whole milk
05 - 0.5 cup heavy cream
06 - 3 large eggs

→ Meats

07 - 8 slices cooked ham, approximately 7 ounces

→ Béchamel Sauce

08 - 2 tablespoons unsalted butter
09 - 2 tablespoons all-purpose flour
10 - 1.25 cups whole milk
11 - 0.25 teaspoon ground nutmeg
12 - Salt and black pepper to taste

# Preparation steps:

01 - Preheat oven to 375°F. Lightly butter a 9x13-inch baking dish and set aside.
02 - Melt 2 tablespoons butter in a medium saucepan over medium heat. Whisk in flour and cook for 1 minute until paste forms. Gradually whisk in 1.25 cups milk, stirring constantly, until thickened and smooth, approximately 3-4 minutes. Season with nutmeg, salt, and pepper. Remove from heat.
03 - Butter one side of each bread slice evenly.
04 - Arrange half the bread slices buttered side down in the prepared baking dish in a single layer.
05 - Top bread layer with half the ham slices, then distribute half the grated Gruyère cheese evenly over the ham.
06 - Place remaining bread slices buttered side down over the cheese layer. Top with remaining ham slices and Gruyère cheese.
07 - Whisk together eggs, 1 cup milk, heavy cream, and a pinch of salt in a mixing bowl until well combined.
08 - Pour custard mixture evenly over the layered casserole, pressing gently with the back of a spoon to allow bread to absorb liquid.
09 - Pour prepared béchamel sauce over the top layer and spread evenly to cover the entire surface.
10 - Bake uncovered for 35-40 minutes until puffed, golden brown on top, and bubbling at the edges. Remove from oven and allow to rest for 10 minutes before serving.

# Expert advice:

01 -
  • It tastes like a fancy French bistro brunch but comes together in about an hour with ingredients you probably already have.
  • You can assemble it the night before and just pop it in the oven when guests arrive, which saved me more than once.
  • The crispy top and creamy center make every bite feel indulgent without being too heavy.
  • Leftovers reheat beautifully, and honestly taste even better the next day when the flavors have melded together.
02 -
  • Let the casserole rest for a full 10 minutes after baking or it will be too loose and soupy when you try to serve it.
  • Press the bread down gently after pouring the custard so every slice gets soaked, otherwise you'll end up with dry spots.
  • Don't skip the nutmeg in the béchamel because it adds a warmth that makes the whole dish taste more complex.
  • If your béchamel looks lumpy, whisk it off the heat for a minute and it will usually smooth out on its own.
03 -
  • Grate your own Gruyère instead of buying pre-shredded because it melts smoother and tastes sharper.
  • Let the béchamel cool for a few minutes before spreading it so it doesn't sink into the custard layer.
  • If you want extra flavor, brush a thin layer of Dijon mustard on the buttered bread before layering.
  • Use a glass or ceramic baking dish instead of metal so you can see when the edges are perfectly golden.
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