I’m excited to share my Croissant Breakfast Casserole, an overnight make ahead brunch centerpiece that will have guests asking for seconds.

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I’ll often make this for holiday mornings when I want something mostly hands off but still impressive. Using torn croissants and shredded gruyere, I stack them in a pan and let the mixture sit overnight so the flavors mingle, then bake until puffed and golden.

The first forkful always makes people stop talking because it’s flaky and rich yet not fussy. It’s become my go-to for Croissant Breakfast Casserole and a real hit for Easy Brunch gatherings.

You might think it’s complicated but honestly it feels like cheating, and you’ll want to hide the recipe so everyone asks for seconds.

Ingredients

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Flaky croissants: rich buttery bread that soaks custard, adds decadent texture and carbs
Eggs: protein packed, binds the casserole, gives structure and silky custard
Milk and cream: add creaminess, calories and fat, makes custard tender and rich
Gruyere or Swiss: nutty melty cheese, adds savory depth and calcium and protein
Ham or bacon: salty, smoky meat for savory umami, adds protein and sodium
Maple syrup: optional touch of sweetness, balances salt, adds subtle caramel notes
Shallot or onion: mild sharpness, adds aromatics and a little fiber and carbs
Chives or parsley: fresh herb finish, low calorie, brightens rich and salty flavors

Ingredient Quantities

8 large croissants, torn into about 6 cups worth

8 large eggs

2 cups whole milk

1 cup heavy cream

1 teaspoon Dijon mustard

1 teaspoon kosher salt

1/2 teaspoon freshly ground black pepper

2 cups shredded gruyere or Swiss cheese, about 8 ounces

8 ounces diced cooked ham or 1 cup cooked bacon crumbles

1 small shallot or 1/4 cup finely chopped onion optional

2 tablespoons chopped fresh chives or parsley for garnish optional

1 tablespoon pure maple syrup optional for a touch of sweetness

Butter or cooking spray for the baking pan

How to Make this

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1. Butter or spray a 9×13 inch baking dish and tear 8 large croissants into about 6 cups of pieces, tossing them into the dish; day old croissants soak better but fresh work fine.

2. Preheat oven to 350°F (175°C) but dont turn it on yet if you plan to chill overnight; cook bacon until crisp and crumble or dice 8 ounces cooked ham, and finely chop 1 small shallot or 1/4 cup onion if using.

3. In a large bowl whisk 8 large eggs with 2 cups whole milk, 1 cup heavy cream, 1 teaspoon Dijon mustard, 1 tablespoon pure maple syrup if you want a hint of sweet, 1 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper until smooth.

4. Scatter 2 cups shredded gruyere or Swiss (about 8 ounces) over the croissant pieces, then add the diced ham or bacon and the shallot/onion evenly.

5. Pour the egg and milk mixture evenly over everything, pushing down gently so most croissant pieces are submerged and soaked; press with a spatula to remove air pockets.

6. Cover tightly with foil or plastic wrap and refrigerate at least 4 hours but preferably overnight so the custard fully soaks in.

7. When ready to bake remove from fridge 20 to 30 minutes to take the chill off, then preheat oven to 350°F (175°C) if you didnt already.

8. Bake covered for about 30 to 35 minutes, then remove the cover and bake another 10 to 20 minutes until the center is set and the top is golden and slightly puffed.

9. Let the casserole rest 10 to 15 minutes so it firms up, then taste and add more pepper or a little flaky salt if needed; garnish with 2 tablespoons chopped fresh chives or parsley if you like.

10. Slice and serve warm. Leftovers refrigerate well and reheat in a 325°F oven until warmed through.

Equipment Needed

1. 9×13 inch baking dish, buttered or sprayed
2. Large mixing bowl for the custard and soaking the croissant pieces
3. Whisk (you really want a good one so the eggs stay smooth)
4. Measuring cups and spoons
5. Box grater or microplane for the gruyere
6. Skillet or baking sheet plus tongs or a spatula to cook bacon or warm ham
7. Rubber spatula to press the croissant down and scrape the bowl
8. Cutting board and a sharp knife to tear croissants and chop shallot/ham
9. Foil or plastic wrap to cover while it soaks, plus a kitchen timer or oven timer

FAQ

Q: Can I assemble this casserole the night before? A: Yes, you can assemble and cover it tightly then refrigerate 8 to 24 hours. Overnight lets the custard soak into the croissant for great texture, just dont leave it much longer or the pastry can get mushy.

Q: What oven temp and how do I know when it is done? A: Bake at 350°F (175°C) for about 45 to 55 minutes until the top is golden and the center feels set. An instant read thermometer should register about 160 to 165°F. If the top is browning too fast, tent with foil.

Q: Can I make this ahead and freeze it? A: Yes. For best results assemble, cover tightly and freeze up to 1 month. Thaw in the fridge overnight then bake as directed, you might need 10 to 20 extra minutes. Or bake first, cool, wrap and freeze; reheat at 325°F for 20 to 30 minutes.

Q: What can I swap for the milk and cream, or the cheese? A: You can use half and half instead of milk plus cream for a slightly lighter custard. For dairy free use unsweetened oat or soy milk and a dairy free shredded cheese but expect a different texture and less richness.

Q: How do I avoid a soggy bottom? A: Use day old croissants or toast the pieces lightly so they hold up to the custard. Don't overpour the custard; press croissant pieces gently so they absorb evenly. Let the casserole rest 10 to 15 minutes after baking so it firms up before you serve.

Q: Can I make it vegetarian or sweet? A: Yes. For vegetarian skip the ham and add sautéed mushrooms, spinach, or roasted peppers. For a sweet version leave out the cheese and bacon, stir 1 tablespoon maple syrup into the custard and add berries or sliced apples before baking.

Overnight Croissant Breakfast Casserole: Holiday Brunch Recipes Substitutions and Variations

Croissants: swap for about 6 cups torn brioche or challah (day old works best). A bit denser than croissants but soaks the custard really well, and gives a rich buttery bite.
Gruyere or Swiss cheese: use 2 cups sharp white cheddar or fontina instead. Cheddar adds more bite, fontina melts super smooth. If the cheese is salty, cut back on the kosher salt.
Whole milk and heavy cream: replace both with 3 cups half and half for similar richness and simpler measuring. Great when you dont have heavy cream on hand.
Diced ham or bacon: try 8 ounces cooked crumbled breakfast sausage for a savory meaty swap, or 2 cups roasted mushrooms plus spinach for a vegetarian option. If using sausage skip extra salt.

Pro Tips

1) Stale croissants soak way better than fresh, so if yours are soft let them sit uncovered for a few hours or give them a quick moment in a low oven to dry out a bit, otherwise you’ll get gummy spots.
2) Dont over-salt the custard up front if you’re using bacon or ham, those add a lot of salt; hold back a little and finish with flaky salt at the table if needed.
3) Grate the cheese fresh and fold most of it into the mix but save a handful for the top, that way the interior is creamy and the top gets that nice golden, slightly crisp crust.
4) Overnight chilling is worth it, push the croissant pieces down so theyre well soaked and you avoid dry pockets; if you’re in a hurry pour the custard warm, not hot, to speed absorption.
5) Let the casserole rest after baking so it firms up, and if the top browns too fast tent loosely with foil while the middle finishes, or use a thermometer to pull it at about 165 F for perfectly set custard.

Overnight Croissant Breakfast Casserole: Holiday Brunch Recipes

Recipe by Bob Jones

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I’m excited to share my Croissant Breakfast Casserole, an overnight make ahead brunch centerpiece that will have guests asking for seconds.

Servings

servings

Calories

623

kcal

Equipment: 1. 9×13 inch baking dish, buttered or sprayed
2. Large mixing bowl for the custard and soaking the croissant pieces
3. Whisk (you really want a good one so the eggs stay smooth)
4. Measuring cups and spoons
5. Box grater or microplane for the gruyere
6. Skillet or baking sheet plus tongs or a spatula to cook bacon or warm ham
7. Rubber spatula to press the croissant down and scrape the bowl
8. Cutting board and a sharp knife to tear croissants and chop shallot/ham
9. Foil or plastic wrap to cover while it soaks, plus a kitchen timer or oven timer

Ingredients

8 large croissants, torn into about 6 cups worth
8 large eggs
2 cups whole milk
1 cup heavy cream
1 teaspoon Dijon mustard
1 teaspoon kosher salt
1/2 teaspoon freshly ground black pepper
2 cups shredded gruyere or Swiss cheese, about 8 ounces
8 ounces diced cooked ham or 1 cup cooked bacon crumbles
1 small shallot or 1/4 cup finely chopped onion optional
2 tablespoons chopped fresh chives or parsley for garnish optional
1 tablespoon pure maple syrup optional for a touch of sweetness
Butter or cooking spray for the baking pan

Directions

Butter or spray a 9×13 inch baking dish and tear 8 large croissants into about 6 cups of pieces, tossing them into the dish; day old croissants soak better but fresh work fine.
Preheat oven to 350°F (175°C) but dont turn it on yet if you plan to chill overnight; cook bacon until crisp and crumble or dice 8 ounces cooked ham, and finely chop 1 small shallot or 1/4 cup onion if using.
In a large bowl whisk 8 large eggs with 2 cups whole milk, 1 cup heavy cream, 1 teaspoon Dijon mustard, 1 tablespoon pure maple syrup if you want a hint of sweet, 1 teaspoon kosher salt and 1/2 teaspoon freshly ground black pepper until smooth.
Scatter 2 cups shredded gruyere or Swiss (about 8 ounces) over the croissant pieces, then add the diced ham or bacon and the shallot/onion evenly.
Pour the egg and milk mixture evenly over everything, pushing down gently so most croissant pieces are submerged and soaked; press with a spatula to remove air pockets.
Cover tightly with foil or plastic wrap and refrigerate at least 4 hours but preferably overnight so the custard fully soaks in.
When ready to bake remove from fridge 20 to 30 minutes to take the chill off, then preheat oven to 350°F (175°C) if you didnt already.
Bake covered for about 30 to 35 minutes, then remove the cover and bake another 10 to 20 minutes until the center is set and the top is golden and slightly puffed.
Let the casserole rest 10 to 15 minutes so it firms up, then taste and add more pepper or a little flaky salt if needed; garnish with 2 tablespoons chopped fresh chives or parsley if you like.
Slice and serve warm. Leftovers refrigerate well and reheat in a 325°F oven until warmed through.

Notes

Below you’ll find my best estimate of this recipe’s nutrition facts. Treat the numbers as a guide rather than a rule—great food should nourish both body and spirit. Figures are approximate, and the website owner assumes no liability for any inaccuracies in this recipe.