This overnight sausage, egg, and croissant breakfast bake is the perfect way to start the day! It’s delicious, filling and super easy to prep!
We’re big breakfast eaters at our house, especially on special occasions. I usually like to whip up a quiche or frittata but sometimes the prep can be a bit time-consuming. That’s where this breakfast bake comes in!
Favorite Croissant Breakfast Casserole
There are three reasons this croissant breakfast casserole is my favorite!!
- It’s made a day in advance, which means ALL of the dishes can be cleaned up and put away the night before.
- It’s made in a shock-proof glass baking dish, no need to let it sit at room temperature before you put it in the hot oven.
- It’s basically a complete meal all in one.
How to Make Croissant Breakfast Casserole
To start, in a large skillet, brown the sausage (I used regular but if you love maple or Italian you can use that too) over medium heat until it’s fully cooked. Transfer to sausage a paper towel-lined plate, then remove the grease by patting it with the paper towels. Place the sausage in a medium mixing bowl and set aside.
Wipe the pan out a bit, then sauté the onion until translucent, add a good cup full of spinach and wilt. Add to the bowl with the sausage, then toss with a blend of Monterey and cheddar cheese and cubed croissants.
Spread into the bottom of an 8×8-inch baking pan. I used my OXO glass bakeware dish because I LOVE that it’s made with thermal shock resistant glass, which means it can go from freezer to oven or microwave without cracking!! It’s perfect for overnight bakes or freezer meals! It’s part of their brand new 14 Piece Glass Bake, Serve & Store Set.
Next, in a medium mixing bowl, whisk together the eggs, milk, half and half, mustard (its the “secret” ingredient in this dish), salt, black and pepper, paprika, and garlic powder.
Pour over the mixture in the pan, taking care to soak the tops of all of the croissant pieces. Cover and refrigerate overnight.
Preheat the oven to 350 degrees. Bake uncovered for 45-50 minutes or until the center is set and the tops of the croissants are golden brown. Remove from the oven and allow to rest for 10 minutes before serving.
Cut up the bake and serve with salsa or hot sauce, if desired. Though it’s not really necessary because this dish is so amazing on its own! It’s packed with protein and flavor, and even has a bit of spinach too, which means it’s kind of a balanced meal, right? Ok, so serve it up with a bit of fruit and then you can call it good.
Variations + Tips
I also love that this breakfast casserole can easily be customized to your tastes! Some easy swaps could be:
- swap the sausage for bacon or ham
- swap cheddar and Monterey jack cheese for swiss, mozzarella and/or Gruyere cheese!
- Or add broccoli, mushrooms, bell peppers, and/or sun-dried tomatoes
This recipe is already very quick but you can speed it up by using leftover hamburger meat, or pre-cooked sausage/bacon!
How does the baking time change in a 9×13 pan? Since the dish won’t be at thick I suggest that you keep an eye on it, since it would cook quicker. I would check it after 30 minutes instead of waiting 45 minutes upfront.
Can you make this the morning of? I recommend making it the night before baking so that the bread can soak up all the goodness and flavor! If you are making it the morning of, let the bread sit for at least 20-30 minutes before popping it in the oven. If the bread isn’t soaked through enough there’s a chance of it burning or becoming really hard and crunchy in the casserole.
Making Ahead, Storing + Freezing
Obviously, this is a make-ahead recipe and can be made up to 24 hours in advance! However, you may need or want to make this even early than just the day before!
Follow the recipe until you are ready to bake, then cover and freeze for up to 3-6 months. Take it out the night before you plan to bake it and let it thaw in the fridge overnight. Then you should be good to bake it in the morning.
Once this is refrigerated after baking the crispy croissant pieces won’t be so crispy. My suggestion is to warm it in the oven if you want that texture, but if you don’t care then I would suggest just popping it in the microwave until it’s warmed through. When warming it in the oven preheat it to 350 and then let it warm for about 30 minutes or until it’s warmed through. Bake it uncovered so that the bread can dry out a little bit more!
I can’t wait for you to make this breakfast casserole and for you to fall in love with it, just like I have!! It is perfect for a lazy weekend, a busy morning or when you have company over!!
Other breakfast casserole recipes:
Overnight Sausage, Egg and Croissant Breakfast Bake Recipe
- 1/2 lb regular pork sausage
- 1/2 small onion - or 1 large leek, diced
- 1 cup fresh spinach - roughly chopped
- 1/2 cup cheddar cheese - grated
- 1/2 cup monterey jack cheese - grated
- 3 large croissants - cut or torn into 1-2 inch cubes
- 6 large eggs
- 3/4 cup whole milk
- 1/2 cup half and half
- 3/4 tsp dry mustard
- 1/2 tsp salt
- 1/2 tsp ground black pepper
- 1/4 tsp paprika
- 1/8 tsp garlic powder
- In a large skillet, brown the sausage over medium heat until fully cooked. Transfer the sausage to a paper towel lined plate. Remove the grease by slightly patting with the paper towels, then place in a medium mixing bowl. Wipe the pan out a bit, then saute the onion until translucent, add the spinach and wilt. Add to the bowl with the sausage, then toss with the cheese and cubed croissants. Spread into the bottom of a 8x8-inch baking pan.
- In a medium mixing bowl whisk together the eggs, milk, half and half, mustard, salt, black and pepper, paprika, and garlic powder. Pour over the mixture in the pan, taking care to soak the tops of all of the croissant pieces. Cover and refrigerate for at least 8 hours, preferably overnight.
- Preheat the oven to 350 degrees. Bake uncovered for 45-50 minutes or until the center is set and the tops are golden brown. Remove from the oven and allow to rest for 10 minutes before serving.
Why I love the 14 Piece Glass Bake, Serve & Store Set:
- Glass Bakeware
- Raised, slosh-proof lid for easy transportation and storage without squishing your baked goods
- Convenient, easy-to-read size markings on the container
- Wide, comfortable handles that work with oven mitts
- SNAP Glass Food Storage
- Lids are interchangeable between SNAP Glass line and SNAP Plastic line
- Stackable and nestable
- Microwave safe (lid is too, just undo the tabs first!)
- Leak-proof seal
This set is seriously amazing. I love the lids and how easy the dishes are to store. I love that they have handles and lips, and most importantly- I LOVE that the bakeware is shock-proof.
Buy this set for yourself and family and friends! It will not disappoint!