Overnight Croissant Breakfast Casserole

Introduction

Bring a touch of Parisian flair to your holiday brunch with this Overnight Croissant Breakfast Casserole! Buttery, flaky croissants soak up a rich custard packed with savory sausage, cheese, and vibrant vegetables for a show-stopping crowd-pleaser. The magic? With just a bit of prep the night before, you only need to pop it in the oven in the morning—leaving you more time to relax and enjoy the festive company.

Why This Overnight Croissant Breakfast Casserole Shines

What sets this casserole apart is its irresistible combination of textures and flavors. Soft, fluffy eggs bind the layers of golden croissants, melty cheese, and hearty sausage. Meanwhile, the subtle crunch from sautéed vegetables brings freshness to every bite. It’s indecently simple, absolutely delicious, and destined to be the centerpiece of any holiday brunch spread.

Layering in Ingredients for Maximum Flavor

Start with a base of high-quality, day-old croissants—it’s the key to soaking up every drop of the savory custard. For your protein, brown some breakfast sausage or swap in ham or bacon if you wish.

Dice your onions, bell peppers, and mushrooms for swift, even cooking. If you want an efficient, uniform dice, the Mueller Pro-Series 10-in-1, 8 Blade Vegetable Chopper saves precious prep time and ensures your bites are just right.

After sautéing the veggies and sausage, layer everything in your favorite large baking dish, scattering shredded cheese over the croissant pieces for irresistible melt-factor.

Easy Overnight Prep and Morning Assembly

The beauty of this recipe lies in its overnight rest—the flavors mingle, and the custard mixture soaks deeply into the croissants for a fluffy, decadent texture. Whisk together eggs, milk, cream, herbs, and seasonings. For a lump-free custard, use the Ninja BL610 Professional 72 Oz Countertop Blender to blend everything smoothly and quickly.

Pour the custard over the croissant layers, then cover and refrigerate overnight. In the morning, just uncover and bake until puffed, golden, and bubbling!

Tips for a Perfect Holiday Brunch Presentation

Remove your casserole from the oven with confidence using the KitchenAid Ribbed Soft Silicone Oven Mitt Set. Let it rest for a few minutes before cutting to keep the layers intact.

To safeguard your holiday table from drips and to create an easy cleanup, lay down a festive-yet-practical Pureegg Plastic Table Cloth Disposable 10 Pack, White. Serve slices warm, paired with fresh fruit or a green salad for balance.

Nutritional Information and Serving Size

This decadent Overnight Croissant Breakfast Casserole yields about 8 hearty servings. Each slice is rich and satisfying, with approximately 350–450 calories per portion, depending on your cheese and sausage choices—a special treat for your holiday table!

Overnight Croissant Breakfast Casserole (Recap)

This casserole is the definition of a holiday brunch hero: decadent, beautiful, and built for easy, low-stress entertaining. With its buttery croissants, fluffy custard, and pockets of gooey cheese, every forkful will have your guests asking for seconds!

Instructions

1. Grease a 9×13-inch baking dish. Tear the croissants into large chunks and arrange half in the bottom of the dish.
2. In a nonstick skillet (a SENSARTE Nonstick Frying Pan Skillet, 9.5 Inch is ideal), cook sausage over medium heat until browned. Use a slotted spoon to transfer the sausage to a plate.
3. Add onions, bell pepper, and mushrooms to the skillet. Sauté until veggies are soft, about 5 minutes. Spread veggies and sausage evenly over croissants in the baking dish.
4. Sprinkle 1½ cups of cheese over the sausage and vegetables, then top with remaining croissant pieces.
5. In a large bowl, whisk together eggs, milk, cream, Dijon mustard, thyme, salt, and pepper. For the most even custard, blend in the Ninja BL610 Professional 72 Oz Countertop Blender if you have one.
6. Pour the egg mixture evenly over the casserole. Gently press the croissants down to ensure they all absorb the custard. Top with the remaining ½ cup of cheese.
7. Cover with foil and refrigerate overnight (or at least 6 hours).
8. In the morning, preheat oven to 350°F. Remove casserole from fridge, uncover, and bake for 45–55 minutes, until puffed and golden. Check with a ThermoPro TP19H Digital Meat Thermometer for Cooking; it should read 160°F in the center.
9. Let casserole rest for 10 minutes. Garnish with chives and serve warm, using oven mitts for safe handling (KitchenAid Ribbed Soft Silicone Oven Mitt Set).

Cook and Prep Times

Prep Time: 25 minutes (plus overnight soak)

Cook Time: 50 minutes

Total Time: 1 hour 15 minutes (plus overnight chilling)

Enjoy your delicious, fuss-free holiday brunch centerpiece!