Overnight Croissant Breakfast Casserole
Overnight Croissant Breakfast Casserole is a dreamy mix of buttery croissants, fluffy eggs, melted cheese, and savory sausage all baked together into one delicious breakfast dish. It’s the perfect dish…
Tip: save now, cook later.Overnight Croissant Breakfast Casserole is a dreamy mix of buttery croissants, fluffy eggs, melted cheese, and savory sausage all baked together into one delicious breakfast dish. It’s the perfect dish for mornings when you want something comforting and special but don’t want to spend hours cooking. The croissants soak up all the flavors overnight, making the casserole extra soft and rich.
I love how easy this casserole is to prepare the night before, which means less stress in the morning and more time to enjoy with family or friends. One of my favorite tips is to use day-old croissants because they soak up the eggs even better without getting soggy. Plus, you can throw in some veggies like spinach or bell peppers if you want to add a little fresh crunch or color.
This casserole is always a crowd-pleaser at brunches or weekend breakfasts. I like to serve it straight from the oven with a simple side of fresh fruit or a cup of coffee. It feels like a warm, cozy hug on a plate and makes any morning feel like a special occasion without much effort at all.
Key Ingredients & Substitutions
Croissants: Croissants are the star here. Their buttery, flaky texture soaks up the egg mixture beautifully. I like using day-old croissants; they hold up better without turning mushy. If you can’t find croissants, brioche works well as a substitute.
Eggs & Dairy: Eggs and whole milk or half-and-half create a creamy custard. For a lighter version, try using low-fat milk or a plant-based milk like oat milk. The custard is key to making the casserole soft and rich.
Meat: Breakfast sausage adds flavor and a savory punch. You can swap it with cooked bacon, ham, or keep it vegetarian with sautéed mushrooms or spinach.
Cheese: Cheddar cheese is my go-to for its sharpness and meltiness, but mixing in Swiss or mozzarella offers a great creamy texture. Feel free to use your favorite cheese blend.
How Do I Make Sure the Casserole Soaks Up the Egg Mixture Without Getting Soggy?
Letting the casserole sit overnight is the secret to perfect texture! Here’s how:
- Cut croissants into chunks so they absorb egg evenly.
- After pouring the egg mixture over the croissants, press gently with a spatula to help soak up the custard.
- Cover tightly and refrigerate for at least 6 hours or overnight to let the custard fully absorb.
- When baking, don’t cover the dish — this helps the top crisp up nicely.
Giving the casserole a little resting time after baking also helps it set, making it easier to cut into neat portions.
Equipment You’ll Need
- 9×13-inch baking dish – perfect size to hold the casserole evenly and bake it through.
- Mixing bowl – for whisking eggs, milk, and seasonings together smoothly.
- Whisk – helps blend the custard ingredients without lumps.
- Knife and cutting board – for chopping croissants, veggies, and meat.
- Aluminum foil or plastic wrap – to cover the dish while it soaks overnight in the fridge.
Flavor Variations & Add-Ins
- Swap breakfast sausage for cooked bacon or diced ham to change the meat flavor.
- Stir in diced spinach or kale for a green veggie boost and freshness.
- Use pepper jack or mozzarella cheese for a milder, creamier melt.
- Add a pinch of smoked paprika or garlic powder to the eggs for extra warmth and depth.
Overnight Croissant Breakfast Casserole
Ingredients You’ll Need:
Main Ingredients:
- 5 large croissants, cut into 2-inch chunks
- 8 large eggs
- 2 cups whole milk or half-and-half
- 1 teaspoon Dijon mustard (optional, for flavor)
- ½ teaspoon salt
- ¼ teaspoon freshly ground black pepper
- 8 oz cooked breakfast sausage, crumbled (or cooked bacon or ham pieces)
- 1 cup shredded cheddar cheese (or a mix of cheddar and Swiss)
Optional Vegetables & Garnishes:
- ½ cup diced bell peppers
- ¼ cup diced onions
- 1-2 tablespoons fresh chopped chives or parsley for garnish
How Much Time Will You Need?
This casserole requires about 20 minutes of preparation time. Since it soaks overnight, allow at least 6 hours (or overnight) in the refrigerator for best results. Baking time is about 45-55 minutes. Plan for a total of roughly 7 hours including chilling and baking.
Step-by-Step Instructions:
1. Prepare Your Baking Dish and Croissants:
Begin by lightly greasing a 9×13-inch baking dish with butter or non-stick spray. Cut the croissants into 2-inch chunks and spread them evenly in the dish. This sets the base for your casserole.
2. Mix the Egg Custard:
In a large bowl, whisk together the eggs, whole milk (or half-and-half), Dijon mustard if you like, salt, and freshly ground black pepper until combined and smooth.
3. Add Meats, Veggies, and Cheese:
Sprinkle cooked sausage or your choice of bacon or ham evenly over the croissant pieces. Add diced bell peppers and onions if you’re using them. Pour the egg mixture all over, pressing lightly to ensure the croissants soak up the custard. Finally, top with shredded cheese.
4. Chill Overnight:
Cover your baking dish tightly with plastic wrap or foil and place it in the refrigerator. Let it soak overnight or for at least 6 hours. This step lets the croissants absorb the egg mixture for a tender and flavorful casserole.
5. Bake to Golden Perfection:
When you’re ready, preheat your oven to 350°F (175°C). Remove the cover and bake the casserole uncovered for about 45 to 55 minutes. You want the center set and the top nicely golden and a bit crispy.
6. Rest and Serve:
Allow the casserole to rest for about 5 to 10 minutes to make it easier to cut. Garnish with fresh chopped chives or parsley for a pop of color. Serve warm, alongside fresh fruit or a light salad for a complete breakfast or brunch.
Can I Use Frozen Croissants for This Casserole?
Yes, you can! Just make sure to thaw them completely before cutting into chunks and assembling the casserole. Thaw overnight in the fridge for best results.
How Long Can I Store Leftovers?
Store leftovers in an airtight container in the refrigerator for up to 3 days. Reheat gently in the oven or microwave until warmed through.
Can I Make This Casserole Without Meat?
Absolutely! Skip the sausage and add extra veggies like spinach, mushrooms, or tomatoes to keep it hearty and delicious.
Is It Okay to Use Milk Instead of Half-and-Half?
Yes, whole milk works great and makes the casserole lighter. Half-and-half will give it a richer, creamier texture but both produce tasty results.