Croque Monsieur Casserole

Featured in: Wheat-Warm Everyday Dinners

This Croque Monsieur Casserole elevates the beloved French sandwich into an impressive baked dish. Layers of buttered white bread are stacked with savory ham and nutty Gruyère cheese, then soaked in a rich custard mixture of eggs, milk, and cream. A velvety béchamel sauce crowns the top, creating a golden, bubbling masterpiece. Ready in just one hour, this comforting casserole serves six and pairs beautifully with a crisp green salad and white wine for an elegant brunch or dinner.

Updated on Fri, 30 Jan 2026 14:27:00 GMT
Golden, puffed Croque Monsieur Casserole with bubbly Gruyère cheese, layered ham, and buttery bread fresh from the oven. Save
Golden, puffed Croque Monsieur Casserole with bubbly Gruyère cheese, layered ham, and buttery bread fresh from the oven. | wheatsprig.com

My neighbor brought this to a potluck once, and I stood by the dish until I could sneak a second helping. It had all the richness of a croque monsieur but none of the fuss of flipping sandwiches in a skillet. The edges were crispy, the center soft and custardy, and the béchamel on top had turned into a golden, bubbling crust. I asked for the recipe that night, and it's been my go-to ever since for lazy Sunday mornings when I want something impressive without the effort.

I made this for my sister's baby shower brunch, and it disappeared faster than the mimosas. One guest asked if I'd catered it, which made me laugh because I'd been in my pajamas assembling it an hour earlier. The smell of toasted Gruyère and nutmeg filled the house, and everyone hovered around the kitchen until I finally pulled it out of the oven. It's the kind of dish that makes people linger at the table, scraping their plates and asking for the recipe before they leave.

Ingredients

  • White sandwich bread: I remove the crusts because they can get tough when baked, and the soft interior soaks up the custard perfectly without turning mushy.
  • Unsalted butter: Softened butter spreads easily on the bread and creates those crispy, golden edges that make every bite satisfying.
  • Gruyère cheese: This is the star, nutty and melty, but Swiss works if you can't find it.
  • Whole milk and heavy cream: Together they create a custard that's rich but not heavy, binding everything into creamy layers.
  • Eggs: They give structure to the custard and help the casserole puff up beautifully as it bakes.
  • Cooked ham: I use deli ham for convenience, but leftover holiday ham works wonderfully and adds even more flavor.
  • All-purpose flour: This thickens the béchamel into a velvety sauce that coats every layer.
  • Ground nutmeg: Just a pinch transforms the béchamel from plain white sauce into something that tastes unmistakably French.

Instructions

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Prep your dish:
Preheat the oven to 375°F and butter your baking dish generously so nothing sticks. This step also adds a little extra richness to the edges.
Make the béchamel:
Melt butter in a saucepan, whisk in flour, and cook for a minute until it smells toasty. Slowly add milk while whisking constantly until the sauce thickens and coats the back of a spoon, then season with nutmeg, salt, and pepper.
Butter the bread:
Spread softened butter on one side of each slice. This creates a crispy top and bottom layer that contrasts beautifully with the custardy center.
Layer the casserole:
Arrange half the bread buttered side down in the dish, then layer ham and cheese. Repeat with remaining bread, ham, and cheese, pressing gently as you go.
Add the custard:
Whisk together eggs, milk, cream, and a pinch of salt, then pour it evenly over the layers. Press down gently so the bread absorbs the liquid without getting soggy.
Top with béchamel:
Pour the warm béchamel over everything and spread it to the edges. This creates that signature golden crust on top.
Bake until golden:
Bake uncovered for 35 to 40 minutes until the top is puffed and bubbling. Let it rest for 10 minutes so the layers set and you can cut clean squares.
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A savory slice of Croque Monsieur Casserole served with a crisp green salad and fresh chives on the side. Save
A savory slice of Croque Monsieur Casserole served with a crisp green salad and fresh chives on the side. | wheatsprig.com

The first time I served this, my husband said it tasted like we were sitting in a Paris café, and I didn't have the heart to tell him I'd made it in sweatpants. It's become our tradition for holiday mornings when we want something indulgent but don't want to stand over the stove. The house smells like a French bakery, and everyone gathers in the kitchen before it's even out of the oven.

Make It Your Own

I've swapped the ham for turkey when I have Thanksgiving leftovers, and once I left it out entirely and layered in sautéed mushrooms and spinach for a vegetarian version. A smear of Dijon mustard between the bread layers adds a sharp, tangy kick that cuts through the richness. You can also use sourdough or brioche instead of white bread for a heartier or sweeter twist.

Timing and Prep Ahead

This casserole is perfect for entertaining because you can assemble it the night before, cover it tightly, and refrigerate it until morning. Just let it sit at room temperature for 20 minutes before baking, and add an extra 5 minutes to the bake time if it's still cold. I've even baked it straight from the fridge in a pinch, and it turned out just fine.

Serving Suggestions

I always serve this with a simple green salad dressed in lemon vinaigrette to balance the richness. A crisp white wine like Chardonnay or Sauvignon Blanc is perfect alongside it, though coffee and orange juice work just as well for brunch. Leftovers reheat beautifully in the oven at 350°F for about 15 minutes, and honestly, they're even better the next day when the flavors have melded together.

  • Pair with a bright arugula salad to cut through the creamy richness.
  • Serve with fruit like sliced melon or berries for a fresh contrast.
  • Reheat individual portions in the microwave for 90 seconds if you're in a hurry.
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Homemade Croque Monsieur Casserole featuring creamy béchamel sauce, melted Gruyère, and golden toasted bread layers in a baking dish. Save
Homemade Croque Monsieur Casserole featuring creamy béchamel sauce, melted Gruyère, and golden toasted bread layers in a baking dish. | wheatsprig.com

This casserole has saved me on countless mornings when I needed something special without the fuss. It's proof that the best dishes are the ones that taste fancy but let you stay calm in the kitchen.

Recipe Q&A

Can I prepare this casserole ahead of time?

Yes, assemble the casserole up to 24 hours in advance, cover tightly with plastic wrap, and refrigerate. Add 10-15 minutes to the baking time if starting from cold.

What cheese can I substitute for Gruyère?

Swiss cheese, Emmental, or Comté work wonderfully as substitutes. For a sharper flavor, try a combination of Swiss and sharp white cheddar.

How do I make this vegetarian?

Omit the ham and add sautéed mushrooms, caramelized onions, or fresh spinach between the bread layers for a delicious meat-free version.

Why remove the bread crusts?

Removing crusts creates a more tender, uniform texture and allows the custard mixture to soak through more evenly, resulting in a softer, more cohesive casserole.

Can I freeze leftovers?

Yes, cool completely, portion into airtight containers, and freeze for up to 2 months. Reheat in a 350°F oven until warmed through, about 20-25 minutes.

What should I serve alongside this dish?

A crisp green salad with vinaigrette, roasted asparagus, or fresh fruit complement the richness perfectly. Pair with Chardonnay or a light French rosé.

Croque Monsieur Casserole

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

Prep Time
20 min
Time to Cook
40 min
Overall Time
60 min
Recipe By Riley Scott


Skill Level Easy

Cuisine French

Makes 6 Number of Servings

Diet Details None specified

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

01 8 slices cooked ham, approximately 7 ounces

Béchamel Sauce

01 2 tablespoons unsalted butter
02 2 tablespoons all-purpose flour
03 1.25 cups whole milk
04 0.25 teaspoon ground nutmeg
05 Salt and black pepper to taste

Method

Step 01

Preheat and Prepare: Preheat oven to 375°F. Lightly butter a 9x13-inch baking dish.

Step 02

Prepare Béchamel Sauce: 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.

Step 03

Butter Bread: Butter one side of each bread slice.

Step 04

Layer Base: Arrange half the bread slices, buttered side down, in the prepared baking dish.

Step 05

Add First Filling Layer: Top bread with half the ham slices and half the Gruyère cheese.

Step 06

Complete Layers: Repeat with remaining bread slices, buttered side down, then remaining ham and cheese.

Step 07

Prepare Custard Mixture: 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.

Step 08

Add Sauce Layer: Pour prepared béchamel sauce over the top and spread evenly.

Step 09

Bake: Bake uncovered for 35 to 40 minutes, until puffed, golden brown, and bubbling at the edges.

Step 10

Rest and Serve: Allow casserole to rest for 10 minutes before serving.

What You’ll Need

  • 9x13-inch baking dish
  • Medium saucepan
  • Whisk
  • Mixing bowls
  • Bread knife

Allergy Info

Review every ingredient for allergens and speak with a healthcare provider if you’re unsure.
  • Contains wheat (gluten)
  • Contains milk
  • Contains eggs
  • Contains pork

Nutritional info (per portion)

This data is just a guideline and shouldn’t replace medical input.
  • Energy (kcal): 420
  • Fat Content: 25 g
  • Carbohydrates: 28 g
  • Proteins: 21 g