The first time I took a bite of a Croque Monsieur, I was captivated by its blend of crispy bread, rich ham, and gooey, melting cheese, all enveloped in a dreamy béchamel. That unforgettable experience inspired me to transform this classic French sandwich into a breakfast casserole that’s not only easy to whip up but utterly comforting. Imagine waking up to the inviting aroma of Gruyére cheese mingling with the warmth of nutmeg; it creates an irresistible atmosphere perfect for family gatherings or brunch with friends.

This Croque Monsieur Breakfast Casserole is a brilliant solution to the age-old dilemma of feeding a crowd without spending all morning in the kitchen. Just make it ahead of time and let the magic happen in the oven. Fluffy, creamy, and with just the right amount of crunch, every slice feels like a delightful hug on a plate. Whether you’re enjoying it on a lazy Sunday or serving it at a festive gathering, this dish is sure to impress. Let’s dive into this recipe that promises to turn any meal into a special occasion!

Why is Croque Monsieur Breakfast Casserole special?

Decadent flavors: This casserole melds the savory richness of ham and Gruyére cheese with a silky béchamel, ensuring every bite is packed with flavor.
Make-ahead magic: Prep it the night before, and enjoy a stress-free morning, perfect for entertaining!
Crowd-pleaser: Its charming blend of classic French tastes wins over even picky eaters, making it a go-to for gatherings.
Versatile options: You can easily customize with different cheeses or add veggies, accommodating all dietary preferences.
Effortlessly impressive: With minimal effort, you can serve a dish that looks and tastes gourmet, elevating your brunch game!

Croque Monsieur Breakfast Casserole Ingredients

For the Casserole
• Country-Style Bread – Provides structure and base for the casserole; use day-old bread for better absorption of the egg mixture.
• Large Eggs – Binds the ingredients and brings richness to each bite.
• Half-and-Half – Adds creaminess to the custard; substitute with whole milk for a lighter version.
• Dijon Mustard – Imparts a tangy flavor; can be omitted if a milder taste is preferred.
• Kosher Salt – Enhances overall flavor; adjust according to your taste.
• Freshly Ground Black Pepper – Adds great seasoning; white pepper can be used for a milder flavor.
• Unsalted Butter – Greases the pan and enhances flavor; cooking spray works as a quick substitute.

For the Filling
• Shredded Gruyére Cheese – The main cheese providing richness and flavor; swap with Swiss cheese for a different taste.
• Ham – Adds protein and flavor; cooked bacon or sautéed spinach can be used for a vegetarian option.

For the Béchamel Sauce
• All-Purpose Flour – Thickens the sauce; substitute with gluten-free flour if needed.
• Whole Milk – Combines with the béchamel sauce; consider non-dairy alternatives for lactose-free versions.
• Ground Nutmeg – A pinch adds warmth and complexity; optional based on preference.

Let these carefully selected ingredients come together for your Croque Monsieur Breakfast Casserole, transforming your breakfast or brunch into something special!

How to Make Croque Monsieur Breakfast Casserole

Preheat your oven to 350°F (175°C). Grease a baking dish with unsalted butter to ensure a perfect non-stick finish for your casserole.
Cut the country-style bread into 1-inch cubes, then layer them evenly in your greased dish, creating a solid base for the delicious filling.
Whisk together the large eggs, half-and-half, Dijon mustard, kosher salt, and freshly ground black pepper in a bowl until smooth; this mixture will create the creamy custard that binds everything together.
Pour the egg mixture over the bread cubes, gently pressing down as you go to make sure every piece is well-coated and soaked in that yummy custard.
Melt 2 tablespoons of unsalted butter in a saucepan over medium heat. Whisk in all-purpose flour to form a roux, then slowly add whole milk, stirring continuously until the sauce thickens. Finish by seasoning with a pinch of ground nutmeg for warmth.
Pour the béchamel sauce over the soaked bread mixture. Sprinkle half of the shredded Gruyére cheese and diced ham evenly over the top, making sure to distribute them well.
Bake in the preheated oven for 1 hour, or until the top is golden brown and the casserole is set. Let it cool slightly before serving to enhance flavors.

Optional: Serve with a sprinkle of fresh parsley for a pop of color!

Exact quantities are listed in the recipe card below.

Expert Tips for Croque Monsieur Breakfast Casserole

Day-Old Bread: Make sure to use day-old country-style bread for the best absorption of the egg mixture. Fresh bread may become too soggy.
Even Coating: Ensure every bread cube is thoroughly coated in the egg mixture. This avoids dry spots, leading to an uneven texture in your casserole.
Chill Overnight: For maximum flavor, assemble your Croque Monsieur Breakfast Casserole the night before and let it sit in the refrigerator. Just bring it to room temperature before baking.
Béchamel Consistency: Whisk the béchamel sauce continuously while adding milk to prevent lumps and achieve a smooth, creamy texture.
Customize with Veggies: Feel free to incorporate sautéed veggies like spinach or mushrooms for added nutrients and variety, making it a flexible dish for all palates.
Let it Rest: Allow the casserole to rest for about 10-15 minutes after baking. This will help it set and make for easier slicing.

Croque Monsieur Breakfast Casserole Variations

Customize your casserole and treat yourself to exciting flavor profiles with these delightful twists!

Vegetarian Delight: Swap ham for sautéed spinach or mushrooms to create a hearty veggie version that still satisfies.
Cheesy Goodness: Experiment with different cheeses like cheddar, pepper jack, or even a sharp blue cheese for unique flavor combinations that open a new world of taste.
Tomato Burst: Add diced tomatoes or sun-dried tomatoes for a fresh, tangy twist that brightens each bite.
Smoky Flavor: Incorporate smoked ham or bacon for a deeper flavor profile that brings warmth and comfort to your casserole.
Herb Infusion: Stir in fresh herbs like thyme or rosemary into the egg mixture to elevate the bouquet of flavors, adding a refreshing touch.
Gluten-Free Option: Use gluten-free bread and swap all-purpose flour with a gluten-free alternative to keep it accessible for everyone.
Sweet Heat: For a surprising kick, mix in some diced jalapeños or a sprinkle of red pepper flakes to provide warmth and excitement.
Nutty Crunch: Top with toasted breadcrumbs or crushed nuts before baking to add a delightful crunch that contrasts with the soft custard.

Feel free to mix and match these ideas to create a version of the Croque Monsieur Breakfast Casserole that’s uniquely yours!

What to Serve with Croque Monsieur Breakfast Casserole?

A delicious breakfast or brunch is made complete with the perfect side dishes and drinks that elevate your meal experience.

Mixed Greens Salad: A light salad with a zesty vinaigrette balances the richness of the casserole, adding freshness and brightness.
Fresh Fruit Platter: Juicy seasonal fruits bring a sweet contrast and refreshing touch, making your brunch feel vibrant and colorful.
Herbed Roasted Potatoes: Crispy potatoes with rosemary and garlic offer a lovely crunch, enhancing the meal’s heartiness while adding comforting flavors.
Savory Quiche: A slice of quiche provides an additional layer of flavor with its unique fillings, creating a delightful ensemble on the table.
Sparkling Wine: A glass of bubbly elevates your brunch, adding a festive touch that pairs beautifully with the creamy, savory notes of the casserole.
Coffee or Espresso: Start your morning with a rich cup of coffee, which complements the dish well, enhancing the warm, comforting experience.

With these complementary dishes and beverages, your Croque Monsieur Breakfast Casserole transforms into an unforgettable brunch that everyone will enjoy!

Make Ahead Options

These Croque Monsieur Breakfast Casserole is perfect for busy home cooks looking to save time! You can assemble the casserole up to 24 hours in advance. Simply layer the bread, pour the egg mixture over, and cover it tightly with plastic wrap before refrigerating. This not only enhances the flavors but ensures the bread absorbs all the creamy goodness. When you’re ready to bake, let it sit at room temperature for about 30 minutes to prevent a shock to the dish. It can also be stored in the fridge for up to 3 days before baking. Just remember, cover it well to maintain moisture, and you’ll have a delicious crowd-pleaser ready with minimal morning fuss!

Storage Tips for Croque Monsieur Breakfast Casserole

Fridge: Store leftovers in an airtight container for up to 3 days. Allow the casserole to cool completely before refrigerating to maintain its texture.

Freezer: The Croque Monsieur Breakfast Casserole can be frozen for up to 2 months. Wrap tightly in plastic wrap and then in aluminum foil to prevent freezer burn.

Reheating: To reheat, thaw overnight in the fridge, then bake at 350°F (175°C) for about 25-30 minutes, or until heated through. You can cover it with foil to keep it moist.

Make Ahead: Assemble your casserole the night before and refrigerate it overnight. Just remember to bring it to room temperature before baking for best results!

Croque Monsieur Breakfast Casserole Recipe FAQs

What type of bread should I use for the Croque Monsieur Breakfast Casserole?
Using day-old country-style bread is ideal as it provides the right texture and absorbs the custard mixture beautifully. Fresh bread can become too soggy, so I highly recommend letting it dry out a bit before use.

How should I store leftover Croque Monsieur Breakfast Casserole?
Store any leftovers in an airtight container in the refrigerator for up to 3 days. Make sure to allow the casserole to cool completely before refrigerating to help maintain its texture and flavor.

Can I freeze the Croque Monsieur Breakfast Casserole?
Absolutely! You can freeze it for up to 2 months. Just wrap the casserole tightly in plastic wrap and then in aluminum foil to prevent freezer burn. When you’re ready to enjoy it, let it thaw overnight in the fridge before reheating.

What’s the best way to reheat the casserole?
To reheat, first thaw it in the refrigerator overnight. Then, bake at 350°F (175°C) for about 25-30 minutes. Cover it with foil to keep it moist and delicious. This step helps soften the casserole while ensuring it’s heated evenly throughout.

Can I make the casserole ahead of time?
Yes, you can prepare the Croque Monsieur Breakfast Casserole the night before! Simply assemble it fully, cover it, and refrigerate overnight. Just make sure to let it come to room temperature before placing it in the oven for baking.

Is there a vegetarian option for this recipe?
Definitely! You can swap out the ham for sautéed spinach or mushrooms to maintain flavor and texture. This makes the casserole suitable for vegetarians without sacrificing that classic Croque Monsieur taste.