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Perfect for a holiday brunch or a long weekend, this Croque Monsieur Breakfast Casserole is simple to throw together but packed with savory flavors that are sure to satisfy!
When serving brunch for a crowd, I love having an egg-based dish as my centerpiece. While a quiche is always a great option, this casserole is my new showstopper! Creamy, herby, and oh-so savory — and not to mention you don’t need to go through the effort of making pie crust from scratch.
For this recipe, I use day-old croissants, which almost give this casserole bread pudding vibes. It’s inspired by a Croque Monsieur sandwich, which is basically the French version of a basic ham and cheese sandwich. This casserole features chopped black forest ham, Gruyère cheese, Parmesan, thyme, and Dijon mustard, which gives you all the same flavors of the bistro staple but in a brunch-friendly format. The end result has crispy edges, a tender center, and bubbly cheese.
Ingredients:
- Unsalted Butter
- Day-Old Croissants
- Black Forest Ham
- Gruyère Cheese
- Large Eggs
- Whole Milk
- Whole Milk Greek Yogurt
- Kosher Salt
- Freshly Ground Black Pepper
- Garlic Powder
- Dijon Mustard
- Fresh Thyme
- Parmesan Cheese
Step-by-Step:
Step One: Prepare the Oven and Baking Dish
Position one oven rack in the middle and one near the top of the oven. Preheat the oven to 375°F. Grease a 9×13-inch baking dish with butter.
Step Two: layer the Croissants, Ham, and Cheese
Arrange the torn croissants in a single layer in the prepared baking dish. Add the ham and 1 cup of Gruyère cheese, evenly distributing both over the croissants.
Step Three: Make the Egg Mixture
In a medium bowl, whisk together the melted butter, eggs, milk, yogurt, salt, pepper, garlic powder, Dijon, and fresh thyme until well combined.
Step Four: Add Egg Mixture to Baking Dish
Carefully pour the egg mixture into the baking dish, ensuring all croissant pieces are evenly coated. Sprinkle evenly with the remaining 1/2 cup Gruyère and Parmesan cheese.
Step Five: Bake
Transfer to the oven on the middle rack and bake for 30 minutes. After 30 minutes, move the casserole to the higher rack and bake for an additional 15 to 20 minutes, or until the top is a deep, golden brown and the center is set.
Step Six: Cool and serve
Allow to cool for 10 to 15 minutes. Garnish with the remaining thyme and cut into 8 squares. Enjoy!
Recipe FAQs:
Day old croissants are recommended because they dry out enough that they don’t get soggy. The best way to dry them out quickly is to leave them out out on the counter, uncovered, overnight. If you don’t have time to prep ahead, you can bake the croissants in a 375°F oven for about 10 minutes until they’re no longer soft.
This is a great way to use leftover holiday ham! Simply swap in 1 to 2 cups of diced ham in place of the deli ham.
Yes! If you have a large brunch spread with other items, you can definitely cut this into smaller pieces and serve about 12 people.
I hope you enjoy this Croque Monsieur Breakfast Casserole for your upcoming Easter celebration or any brunch plans you have! Comment below once you make this!
want More brunch-friendly Recipes? try these!
Italian Sausage and Arugula Quiche
Old Fashioned Breakfast Casserole
Croque Monsieur Breakfast Casserole
Ingredients
- 4 tablespoons unsalted butter, melted and cooled, plus more for greasing
- 5 cups torn day-old croissant cubes, about 2 inches (from 3 to 4 large croissants)
- 1/2 pound thinly sliced black forest ham, roughly chopped
- 1½ cups shredded Gruyère cheese, divided
- 8 large eggs
- 1½ cups whole milk
- 1/2 cup whole milk Greek yogurt
- 1 teaspoon kosher salt
- 1 teaspoon freshly ground black pepper
- 1 teaspoon garlic powder
- 1 tablespoon Dijon mustard
- 1 tablespoon roughly fresh thyme leaves, plus more for garnish
- 1/2 cup grated Parmesan cheese
Instructions
- Position one oven rack in the middle and one near the top of the oven. Preheat the oven to 375°F. Grease a 9×13-inch baking dish with butter.
- Arrange the torn croissants in a single layer in the prepared baking dish. Add the ham and 1 cup of Gruyère cheese, evenly distributing both over the croissants.
- In a medium bowl, whisk together the melted butter, eggs, milk, yogurt, salt, pepper, garlic powder, Dijon, and fresh thyme until well combined.
- Carefully pour the egg mixture into the baking dish, ensuring all croissant pieces are evenly coated. Sprinkle evenly with the remaining 1/2 cup Gruyère and Parmesan cheese.
- Transfer to the oven on the middle rack and bake for 30 minutes. After 30 minutes, move the casserole to the higher rack and bake for an additional 15 to 20 minutes, or until the top is a deep, golden brown and the center is set.
- Allow to cool for 10 to 15 minutes. Garnish with the remaining thyme and cut into 8 squares. Enjoy!
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
Photography and styling by Eat Love Eats.
Made this and turned out absolutely delicious. Would like to make again for a girls weekend, but I have one coming that is gluten free – what do you suggest would be a good GF swap for the croissants?
You could try some stale English muffins or even a loaf of day-old brioche bread.
This was amazing!! A great thing to make for a group. I prepped in advance by shredding the cheese and slicing the ham ahead of time, but assembled everything (took me 10-15 mins) the morning-of. Delicious!!
Do you think this will work with non-dairy milk/creamer such as Nut Pods? Thank you!
Hi Myka- I haven’t yet tried this but it should work fine! I personally would bump up the egg to one more egg, and use a slightly less neutral, dairy-free milk (or creamer) here to modify!! so 9 eggs, and 1 1/4 DF milk!!! That should help with consistency.
Making this for Christmas morning! I have the same question…
Can it be prepped in advance?!
Thanks for all the amazing recipes!
Hi! This really does taste best when baked fresh, but you can make it up to 24 hours in advance. Just cover the pan tightly and refrigerate until you’re ready to bake. (And be sure to use stale croissants so that they don’t get too soggy!)
Made this for Thanksgiving morning and it was a hit! Followed the recipe exactly – it was so easy to pull together!
I made this for a baby shower I hosted today and so many people raved about it! It was so so yummy. Highly recommend.
That makes me so happy, Kasey!
Hi Alex! Can this be prepped in advance?
I have the same question!
Have you tried to make in advance? I want to make for Christmas morning, but would love to prep the night before…..
Hi! This tastes best when baked immediately, but you can prep it up to 24 hours in advance. Just cover the pan tightly with plastic wrap and refrigerate until you’re ready to bake. (Definitely use super stale croissants so that they don’t get soggy!)
SO GOOD. Such good flavor and texture.
Hi, I’m about to have a baby and I’m trying to decide what to stock my freezer with. Is this something you would be able to freeze/reheat, or is this a better fresh kind of dish? If so can you provide instructions? Thanks!
Hi! It’s always best fresh, but i think will still be fab baked from frozen!
To Freeze:
Let the bake cool completely, then slice into individual portions. Wrap each piece tightly in plastic wrap and place in a freezer-safe bag or container. Freeze for up to 2 months.
To Reheat from Frozen:
For best results, thaw overnight in the fridge, then reheat in a 350°F oven for 15–20 minutes until warmed through. You can also microwave straight from frozen in 30-second bursts, but the texture is best when reheated in the oven.