Croissant Breakfast Casserole
by Sommer Collier — on Feb 11, 2026 I combine flaky, buttery (store-bought!) croissants with crispy bacon, cheese, and eggs to make this truly fabulous croissant breakfast casserole. I’ve made it for countless holiday brunches and love how my secret tangy ingredient gives this savory dish an unexpected kick. Whether I prep it ahead or assemble and bake it right away, it’s an easy, crowd-pleasing breakfast casserole that’s perfect for any large gathering.
I’m a big fan of breakfast casserole recipes, especially the kind you can prep the night before, place in the fridge before bed, then just pop in the oven first thing in the morning. I have many beloved breakfast bakes like this on the site, but this new croissant breakfast casserole is a knockout!
What makes it special: Using big chunks of croissant in a casserole dish creates a fluffy airy base for the egg and dairy mixture. As the breakfast casserole sits, the croissants soak up all the eggs and dairy. Then, as it bakes, the croissants act as a structural element that allows the eggs to get puffier than ever, creating the lightest, fluffiest, tenderest interior. As if that weren’t enough, I’ve added crumbled bacon, sweet sautéed onions, rosemary, smoky Gouda cheese, and a little bit of mustard to create a bold, savory, and decadent flavor. I’m thrilled to say it is now a regular on my brunch menu!
Sommer’s Recipe Highlights
Easy-peasy – I told you how incredibly delicious this casserole is, but have I mentioned how easy it is to actually make? SO easy! I use store-bought croissants and simply sauté some aromatics, mix up a few simple ingredients in a bowl, then combine everything together into one casserole dish and bake. You got this!
Make Ahead – If I plan to serve it for a holiday brunch or special occasion, I like to save myself some day-of time and assemble the breakfast croissant casserole the night before. I wrap the pan in plastic wrap and refrigerate overnight, then uncover and bake in the morning. Whether I bake immediately or assemble ahead of time, the casserole layers are equally flaky, tender, cheesy, and eggy.
Feed a Crowd – I created this recipe to yield 12 generous pieces, which is perfect for big holidays like Christmas, Easter, and Mother’s Day, or any large family gathering. But you can certainly half the recipe and bake it in a 8 x 8-inch square pan, and you’ll still have at least 6 servings.
Key Ingredients and Tips
- Croissants – The croissants can be fresh or day old.
- Bacon – I prefer thick-cut bacon that holds up well to crisping up on the stove.
- Shredded Gouda – Buy a wedge and grate that gouda by hand! It has the best texture and taste.
- Eggs – I always set my eggs on the counter for 15-20 minutes to bring them to room temperature. Cold eggs take longer to cook and can mess up the process.
- Onion – Use white onion for a slightly sharp bite, or more mild and sweet yellow onion if you prefer.
- Half & half – I know some people are going to ask (and hey, I don’t blame you) if plain milk will work instead. Technically, yes. However, the croissant casserole won’t have quite the same thick and rich, custardy texture. Go with half & half if you can.
- Mustard – I love the chunky style French Dijon mustard. But if it’s not available, buy a coarse brown mustard.
- Fresh rosemary – If you can’t find fresh rosemary, do not use dried rosemary unless it’s fully crushed. (It doesn’t soften well while cooking.) Instead, I would use ½ teaspoon of dried thyme.
How to Make
Find the full ingredient proportions, detailed instructions, storage tips, and a video tutorial in the printable form at the bottom of the post.
Prep – I start by preheating the oven to 350 degrees, and while it’s heating, I grease a large 9 x 13-inch (3 quart) baking dish with softened butter. Using butter gets the edges of the croissant casserole nice and crispy while still keeping anything from sticking to the pan, so I prefer to use it over nonstick spray.
Next, I tear the croissants into large chunks. (Talk about a great stress release!) Each full-size croissant will yield about 4-6 pieces. Spread these out evenly in the baking dish.
Then I do all of the other fun prep work: Chopping bacon, dicing onion, chopping rosemary, and shredding the Gouda cheese.
Sauté – Now it’s time for the itty-bitty bit of cooking to do before essentially dumping everything into the casserole and checking out for a while…
I warm a large skillet over medium heat on the stovetop. Once it’s super hot, I add the chopped bacon, stir and cook for a few minutes, then add the onion and rosemary. This continues to cook for another 3-4 minutes while I keep things moving around with my spatula. We want flavor, but not from burning!
Sprinkle – Next, I scoop the bacon and onion deliciousness from the skillet and sprinkle it evenly over the top of the croissant pieces. I recommend using a slotted spoon to scoop, so you just get the crispy and tender pieces without too much bacon grease.
Add the Cheese – Then I evenly sprinkle the shredded gouda on top of the whole thing.
Whisk Time – In a large mixing bowl, I whisk together the eggs, half & half, mustard, salt, and pepper. You can use a regular whisk, but if you have an adorable egg beater like the one I’m using here, this is the perfect time to bust that baby out!
Pour and Soak – The goal is to get every piece of croissant soaked in the egg and milk mixture. So pour slowly and evenly, working your way back and forth across the surface of the casserole.
Chill Time – If you plan on baking in the morning, now is when you cover the dish tightly with plastic wrap and pop the casserole into the fridge.
If you’re baking right away, don’t get too ahead of yourself… For the best texture, I always let the unbaked casserole sit for about 15 minutes on the counter first. This allows the egg and milk mixture to really soak into every nook and cranny, which there are a lot of when you’re cooking with croissants.
Bake! – After 15 minutes, carefully slide the dish into the preheated oven. Bake for 50 minutes, then look for a golden brown crust and check the doneness by sticking a knife into the center. If it seems wet and jiggly, bake for another 10 minutes or so, and check again.
Serving Suggestions
I let the baked casserole rest for 5-ish minutes before cutting into it. This gives the ingredients a moment to firm up together, and makes it easier to slice into neat portions.
As far as what to serve with croissant breakfast casserole, most of what you need in a full meal is already tucked in here… Loads of carbs, and lots of protein from the eggs, cheese, half & half, and bacon.
Feel like you’re missing something? Ah yes, produce! You can do hearty but still healthy(ish) savory sides like a sweet potato hash or baked hash browns. But I usually prefer to pair the savory casserole with fresh fruit, like slices of melon or a simple fruit salad with whatever is in season.
Whether you want a side that’s savory or sweet, I believe bloody Marys and mimosas are always a fantastic idea at brunch with a decadent casserole like this!
Storing Leftovers
Keep leftovers in an airtight container and refrigerate for 3-4 days.
This casserole freezes well, too! When I plan to freeze the whole thing unbaked, I always assemble the casserole in a disposable aluminum pan so it can go straight from the freezer to the oven.
First, I wrap the pan in a layer of aluminum foil. Then I wrap it in a few layers of plastic wrap and freeze it for 2-3 months. If you bake it from frozen, you’ll need to add 20-30 extra minutes to the baking time, and you definitely want to cover the dish loosely with foil around the 40-minute mark to keep it from burning. But I usually let the casserole thaw in the fridge overnight before baking, so then I only have to add another 10 minutes or so to the total bake time.
If you freeze the casserole after baking, I suggest thawing it in the fridge overnight before reheating in a 350-degree oven for 30-40 minutes, or until it’s heated throughout and crisp again on top.
Frequently Asked Questions
Sure! Skip the bacon and instead saute the onion and rosemary in 2 tablespoons of oil.
It’s very important to drain off as much grease as possible from the bacon, as any excess moisture can lead to a soggy casserole.
Also, I carefully pour the milk and egg mixture slowly and evenly across the croissants, so there are no pools of liquid in any one space.
First, you want to set the dish on the counter for a good 15-20 minutes to bring the pan to room temperature. Some casserole dishes will crack if heated in the oven too quickly from a cold state!
When ready to bake, remove the plastic wrap and pop the dish into the oven. The time will be about the same, but might take another 10 minutes or so to bake fully.
If the casserole starts looking a little too dark on top around 30-40 minutes, I cover it loosely with foil. Don’t crimp it down, or you’ll trap in moisture and make the croissant casserole soggy.
More Breakfast Recipes
Croissant Breakfast Casserole
Video
Ingredients
- 8-10 croissants 10 large, 8 XL, or 20 minis
- 6 strips thick-cut bacon about 1 cup, chopped
- 1 cup diced onion
- 2 teaspoons fresh chopped rosemary
- 8 ounces smoked gouda cheese shredded (2 cups)
- 12 large eggs
- 3 cups half & half
- 2 tablespoons coarse Dijon mustard or coarse brown mustard
- Salt and pepper
Instructions
- Preheat the oven to 350°F. Set out a 9 x 13 inch (3-quart) baking dish. Butter the inside of the dish on all sides.
- Tear each croissant into large chunks, about 4-6 chunks per croissant. Spread the croissant pieces into the baking dish. Chop the bacon into small pieces. Dice the onion. Chop the rosemary. Shred the smoked Gouda cheese.
- Set a skillet on the stovetop over medium heat. Add the chopped bacon. Stir and cook the bacon until it’s reddish-brown, then add onions and rosemary to the skillet. Continue to stir and sauté the onions for another 3-4 minutes until soft. Turn off the heat.
- Use a slotted spoon to scoop the onions and bacon out of the grease and sprinkle them over the top of the croissants. Allow the bacon to cool for several minutes. Then add the shredded cheese and gently toss the ingredients into the croissant pieces. Spread out in an even layer.
- Set out a medium mixing bowl. Combine the cracked eggs, half-and-half, coarse mustard, ½ teaspoon of salt, and ¼ teaspoon of cracked black pepper. Whisk well.
- Pour the mixture evenly over the croissant base in the baking dish. Allow the mixture to rest and soak into the croissants for at least 15 minutes before baking. *If making ahead, cover and refrigerate.
- Place the baking dish in the oven, uncovered, for 50-60 minutes, until golden-brown on top and puffed in the center.
- Test the croissant casserole by inserting a knife deep into the center. If the eggs are set, remove from the oven. If the knife comes out wet, bake for another 5-10 minutes. If the casserole starts looking a little too dark on top, you can cover it loosely with foil. Allow the croissant casserole to rest for 5 minutes then cut and serve.
