Croque Monsieur Casserole (Printable)

Buttery bread layered with ham, Gruyère, and creamy béchamel sauce. A French bistro classic reimagined for the oven.

# What You'll Need:

→ Bread & Dairy

01 - 12 slices white sandwich bread, crusts removed
02 - 2 tablespoons unsalted butter, softened, plus extra for greasing
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

# 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 until golden. 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. Arrange half the bread slices in the prepared baking dish with buttered sides facing downward.
04 - Top the bread layer with half the ham slices and half the grated Gruyère cheese. Repeat with remaining bread slices, buttered side down, followed by remaining ham and cheese.
05 - In a mixing bowl, whisk together 3 eggs, 1 cup milk, heavy cream, and a pinch of salt until well combined. Pour this mixture evenly over the casserole, pressing gently to ensure bread absorbs the liquid.
06 - Pour the prepared béchamel sauce over the top layer and spread evenly with a spatula to coat the entire surface.
07 - Bake uncovered for 35-40 minutes until the top is puffed, golden brown, and bubbling at the edges. The internal temperature should reach 160°F.
08 - Remove from oven and allow the casserole to rest for 10 minutes before serving to set the structure.

# Expert Advice:

01 -
  • It delivers all the richness of a French bistro classic without standing over a skillet.
  • The creamy béchamel soaks into every layer, turning simple bread into something luxurious.
  • You can assemble it ahead and bake it when company arrives, looking like a culinary genius.
  • Leftovers reheat beautifully and taste even better the next day.
02 -
  • Don't skip the resting time after baking or the casserole will be soupy and hard to slice cleanly.
  • Press the bread down gently after pouring the custard so every piece absorbs the liquid evenly.
  • If your bread is too fresh, let it sit out for an hour or toast it lightly so it doesn't turn mushy.
03 -
  • Grate your own Gruyère instead of buying pre-shredded for better melting and richer flavor.
  • Whisk the béchamel constantly over medium heat to avoid scorching the bottom of the pan.
  • Use a serrated knife to slice cleanly through the layers without squishing them.
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