Croque Monsieur Casserole (Print View)

Buttery bread layered with ham, Gruyère, and béchamel sauce baked until golden and bubbling. A French bistro classic.

# 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

# Method:

01 - Preheat oven to 375°F. Lightly butter a 9x13-inch baking dish.
02 - In a medium saucepan, melt 2 tablespoons butter over medium heat. Whisk in flour and cook for 1 minute. Gradually whisk in 1.25 cups milk, stirring constantly, 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.
04 - Arrange half the bread slices, buttered side down, in the prepared baking dish.
05 - Top bread with half the ham slices and half the Gruyère cheese.
06 - Repeat with remaining bread slices, buttered side down, then remaining ham and cheese.
07 - Whisk together eggs, 1 cup milk, cream, and a pinch of salt in a bowl. Pour evenly over the casserole, pressing gently to ensure bread absorbs the liquid.
08 - Pour prepared béchamel sauce over the top and spread evenly.
09 - Bake uncovered for 35 to 40 minutes, until puffed, golden brown, and bubbling at the edges.
10 - Allow casserole to rest for 10 minutes before serving.

# Expert Advice:

01 -
  • It tastes like you spent all morning in the kitchen, but most of the work happens in the oven.
  • Leftovers reheat beautifully and somehow taste even better the next day.
  • You can assemble it the night before and just pop it in the oven when guests arrive.
  • It turns a fancy French sandwich into a dish that feeds a crowd without any stress.
02 -
  • Don't skip the resting time after baking or the custard will run all over your plate instead of holding its shape.
  • Press the bread gently into the custard as you pour it so every slice absorbs enough liquid to stay tender.
  • If your béchamel gets lumpy, whisk vigorously off the heat or use an immersion blender to smooth it out.
03 -
  • Use day-old bread because it absorbs the custard better without falling apart or getting too soggy.
  • Grate your own Gruyère instead of buying pre-shredded because it melts smoother and has more flavor.
  • If the top browns too quickly, tent it loosely with foil for the last 10 minutes of baking.
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