Overnight Croissant Breakfast Bake

If you love the ease of breakfast casseroles, you need this recipe for Overnight Croissant Breakfast Bake in your life ASAP! Sausage, onions, sautéed spinach, eggs, and buttery croissants all topped with melty cheese. You have officially died and gone to breakfast casserole heaven!

Overnight Croissant Breakfast Bake

I love a good breakfast casserole. What’s not to love about waking up, turning on the oven, and about an hour later pulling this out of the oven?! Of all the breakfast casserole recipes I have on A Bountiful Kitchen, this one is my favorite, and I believe the best breakfast casserole recipe!

The best breakfast casserole

You may be wondering why I use croissants in this breakfast casserole. The trouble with many breakfast casseroles is they look decent when pulled right out of the oven but quickly deflate into a flat dish that looks less than appetizing. Our Overnight Croissant Breakfast Bake is everything you love in breakfast foods all combined into one beautiful, delicious dish.

favorite breakfast bake

This recipe takes overnight casseroles to the next level. When I first started making breakfast casseroles in the 80’s, recipes often instructed to butter slices of bread, which made the casserole buttery and delicious. The croissants mimic the buttered bread but in a next-level way! The flaky layers of croissants soaked in eggs and half-and-half are similar to a rich bread pudding texture I know you will love!

How to make this easy Breakfast Casserole:

  1. Tear the croissants into pieces and place in a greased 9×13-inch dish.
  2. Brown the sausage, drain grease, and place on top of croissants.
  3. Cook the onion and spinach, pour on top of sausage, and top with cheese.
  4. Beat the eggs with half-and-half and add seasonings.
  5. Pour over cheese in pan.
  6. Cover with foil and refrigerate overnight.
  7. Preheat oven and bake 30 minutes with foil on top, 30 minutes without.
  8. Let cool. Top with chili sauce

Ingredients needed for Overnight Croissant Breakfast Bake:

  • 4-6 large croissants (day old are best)
  • 1 pound Italian or spicy sausage
  • 2 cups chopped onion
  • 1-2 cups fresh spinach
  • 2 cups grated cheddar, Monterey Jack, pepper jack, mozzarella, or a combo
  • 12 large eggs
  • 1 1/2 cups half-and-half
  • 1 teaspoon dry mustard

We like to serve this with sweet rolls, fresh fruit and cocoa!

This recipe originally posted in 2014, updated with new photos and content September 2023.

Overnight Croissant Breakfast Bake

5 from 2 votes
Print Pin
Author: Si Foster
Course: Breakfast, brunch
Cuisine: American
Prep Time: 15 minutes
Cook Time: 1 hour
refrigeration: 8 hours
Total Time: 9 hours 15 minutes
Servings: 12
This easy-to-make breakfast casserole is my favorite of all the breakfast casseroles! Simple yet delicious, with a bit of onions and spinach for color and flavor. The croissants take this ordinary breakfast casserole over the top!

Ingredients 

  • 4-6 large croissants, (day old are best)
  • 1 pound Italian or spicy sausage, (you may use more if desired)
  • 2 cups onions, chopped
  • 1 tablespoon olive oil or butter
  • 2 cups fresh spinach
  • 2 cups grated cheddar, Monterey Jack, Pepper Jack, mozzarella, or a combo
  • 12 eggs
  • 1 1/2 cups half and half
  • 1 teaspoon dry mustard
  • 1 teaspoon salt
  • 1 teaspoon ground pepper

Instructions

  • Grease a 9×13-inch or large casserole dish.
  • Tear the croissants into large pieces. Lay croissant pieces in the casserole dish, covering the bottom of the pan.
  • Brown the sausage in a large pan. Place cooked sausage on a plate lined with paper towels. Press paper towels on the sausage to remove any grease.
  • Distribute the sausage evenly on top of the croissants.
  • Drain grease from the pan and use a paper towel to wipe excess grease from the pan. Cook onions in the same pan for 5 minutes or until softened. Add olive oil or butter if needed. Add spinach and cook just until wilted. Pour cooked onions and spinach over the of sausage and top with grated cheese.
  • In a blender or a large bowl, mix eggs and half-and-half. Add dry mustard, salt, and pepper. Pour this mixture over the casserole.
  • Spray foil with cooking spray. Use the sprayed side of the foil to cover the casserole. Refrigerate overnight.
  • Remove the casserole from the refrigerator 30-60 minutes before baking.
  • Preheat oven to 375 degrees. Place rack in the center of the oven.
  • Bake the casserole, covered, for 30 minutes, then carefully remove the foil and bake until the top is slightly puffed and the eggs are set in the center, about 30 additional minutes.
  • Remove from the oven and cool for 30 minutes. Cut into 12 squares. Serve with chili sauce and or salsa.

Notes

The meat may be cooked and kept in the the fridge for up to three days before assembling the casserole. You may also cook and freeze the meat ahead of time.

Did you make this recipe?

Be sure to leave a comment and give this recipe a rating, letting me know how you liked it. I’d love to see a photo, tag @abountifulkitchen on Instagram!