Croque Monsieur Casserole (Printable)

Layers of buttery bread, ham, Gruyère, and béchamel sauce baked until golden and bubbling for brunch or dinner.

# What You Need:

→ Bread & Dairy

01 - 12 slices white sandwich bread, crusts removed
02 - 2 tablespoons unsalted butter, softened, plus extra for greasing
03 - 1 1/2 cups Gruyère cheese, grated
04 - 1 cup whole milk
05 - 1/2 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 1/4 cups whole milk
11 - 1/4 teaspoon ground nutmeg
12 - Salt and black pepper to taste

# Directions:

01 - Preheat oven to 375°F. Lightly butter a 9x13-inch baking dish and set aside.
02 - In a medium saucepan, melt 2 tablespoons butter over medium heat. Whisk in flour and cook for 1 minute, stirring constantly. Gradually add 1 1/4 cups milk while whisking continuously until thickened and smooth, approximately 3 to 4 minutes. Season with nutmeg, salt, and pepper. Remove from heat.
03 - Butter one side of each bread slice. Arrange half the bread slices, buttered side down, in the prepared baking dish.
04 - Top the bread layer with half the ham slices and half the Gruyère cheese. Repeat with remaining bread slices, buttered side down, remaining ham, and remaining cheese.
05 - In a mixing bowl, whisk together 3 eggs, 1 cup milk, heavy cream, and a pinch of salt until well combined.
06 - Pour the egg custard evenly over the layered casserole, pressing gently to ensure the bread absorbs the mixture. Spread béchamel sauce evenly over the top.
07 - Bake uncovered for 35 to 40 minutes until puffed, golden brown, and bubbling at the edges. Remove from oven and let rest for 10 minutes before serving.

# Expert Advice:

01 -
  • It transforms ordinary sandwich ingredients into something that feels luxurious and special without any fancy techniques.
  • You can prep the whole thing ahead, let it soak in the fridge, and bake it just before guests arrive.
  • Every bite has that perfect balance of creamy béchamel, salty ham, and nutty melted cheese.
  • Leftovers reheat beautifully and somehow taste even better the next day.
02 -
  • Press the bread gently into the custard mixture before baking or you will end up with dry top layers and soggy bottoms.
  • Do not skip the resting time after baking, it lets the custard firm up so your slices hold together instead of falling apart.
  • If the top starts browning too fast, tent it loosely with foil for the last 10 minutes.
03 -
  • Use day-old bread instead of fresh, it absorbs the custard better and holds its shape during baking.
  • Grate the Gruyère yourself instead of buying pre-shredded, it melts smoother and tastes infinitely better.
  • Warm the milk slightly before whisking it into the roux for the béchamel, it prevents lumps and makes the sauce come together faster.
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