Cheesy Croissant Breakfast Casserole is packed full of sausage, sun dried tomatoes, spinach, buttery croissants, and plenty of cheese!  This casserole is great for brunch or dinner!

croissant casserole

Cheesy Croissant Breakfast Casserole:

Let’s have some comfort food today, because this casserole is just TOO GOOD to pass up!  When I created this recipe I actually had dinner in mind, although it would work for breakfast, lunch, or anything.  We all know I am a major brunch fan with anything from Sausage Gravy to Belgian Waffles and I enjoy eating them any time of day, it’s nice to change the dinner routine up a bit.  Who wouldn’t love this casserole?!  It’s full of buttery croissants, Italian (or pork) sausage, sun dried tomatoes, spinach, 2 heaping cups of cheese and a savory/garlic egg mixture.  If you’re going to make this soon, keep in mind that it is an overnight casserole recipe.  But, that means if you want it for dinner, you can throw it together in the morning, then it’s ready to pop in the oven later in the day!

croissant breakfast casseroleyl

Making This Casserole and Recipe Notes:

  • You’ll need 8, full sized croissants from your bakery for this recipe.  Day old croissants are best if you can purchase them ahead.  If not, fresh will still work ok too!
  • Make sure to soak the croissants in the egg/cream mixture!  You will add the torn pieces to the bowl and stir well.  If you pour the egg mixture over the croissants in the pan, the egg all sinks to the bottom.
  • This casserole is best made at least a few hours in advance.  I like to give it at least 8-12 hours for the croissants to really soak up the wet mixture, that way they don’t become too soggy.
  • I love Italian Sausage in this recipe!  It has tons of flavor and tastes great with the sun dried tomatoes.  But, you can always use regular pork/breakfast style sausage if that’s what you have on hand or prefer.
  • Don’t skip the mustard if you can help it!  I know not everyone likes this particular condiment but don’t worry, the casserole doesn’t taste of mustard.  It just helps amp up the flavor a bit.
  • As far as cheese, you can use any that are your favorite!  For this dish, I prefer a mixture of Gruyere, Mozzarella, and Parmesan.  Fontina and cheddar are also great choices.

croissant casserole in dish



5 from 11 votes

Cheesy Croissant Casserole

Cheesy Croissant Breakfast Casserole is packed full of sausage, sun dried tomatoes, spinach, buttery croissants, and plenty of cheese!  This casserole is great for brunch or dinner!
Prep 15 minutes
Cook 30 minutes
Chill Time 8 hours
Total 8 hours 45 minutes
Servings 10


  • 1 Pound Italian or Pork Sausage
  • 3 Tablespoons Butter
  • 1 Small Yellow Onion Diced
  • 8 Ounces Baby Spinach
  • 1/2 Cup Chopped Sun Dried Tomatoes
  • 4 Large Eggs
  • 1 Cup Milk
  • 1/2 Cup Heavy Cream
  • 3 Cloves Garlic Minced
  • 1 teaspoon Dijon Mustard
  • Salt & Pepper to taste
  • 1/4 teaspoon Cayenne Pepper Optional
  • 8 Croissants
  • 2 Cups Cheese - Gruyere Fontina, Parmesan, Mozzarella


  • Grease a 9x13 inch baking dish with butter or non-stick spray, set aside.
  • Cook the sausage in a large skillet over medium-high heat until cooked through and no longer pink, drain and set aside.
  • To the same skillet add the butter. Once the butter is melted, add in the diced onion, spinach, and sun dried tomatoes.
  • Season with a pinch of salt and pepper and cook, stirring constantly for 5 minutes until spinach is wilted and onions are soft.
  • Meanwhile, in a large bowl whisk together the eggs, milk, cream, mustard, garlic salt and pepper, and cayenne if using.
  • Roughly tear the croissants into the bowl of egg mixture, along with half of the cheese, and stir well to combine.
  • Pour the mixture into the prepared baking dish.
  • Sprinkle the cooked sausage, and the spinach mixture, and remaining cheese over the casserole.
  • Cover the dish with foil and refrigerate for at least 2 and up to 12 hours if possible.
  • Preheat oven to 350 degrees. Remove the foil from the dish and bake for 30 minutes until cooked through.
  • Serve immediately. Refrigerate leftovers for up to 3 days.



NOTE ON MAKING AHEAD:  This casserole is best made with day-old croissants if possible.  Make this casserole ahead and chill for at least 2 hours if possible, and up to 12 hours before baking.


Calories: 640kcal, Carbohydrates: 47g, Protein: 19g, Fat: 45g, Saturated Fat: 25g, Cholesterol: 153mg, Sodium: 564mg, Potassium: 369mg, Fiber: 3g, Sugar: 21g, Vitamin A: 3151IU, Vitamin C: 7mg, Calcium: 354mg, Iron: 3mg

Nutrition information is automatically calculated, so should only be used as an approximation.

Additional Info

Course: Breakfast, Main Course
Cuisine: American
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Hey! Nice to meet you! I'm Nichole!

Welcome to The Salty Marshmallow! I'm a mom, animal lover, photographer, & kitchen mess-maker. Here you will find the result of my decades-long passion for chasing the best flavors in the kitchen, all meant to be cooked by regular people with busy lives just like you and me.

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  1. 5 stars
    I made this last night and oh my goodness… what a delicious brinner we had. My kids asked for seconds and my husband didn’t complain one bit. This is a huge milestone.