Name: Elevate Mornings with This Cozy Breakfast Casserole
Prep time: 30 min
Cook time: 50 min
Total time: 200 min
Ingredients: 1 pound Pork Breakfast Sausage (Substitute with turkey sausage for a lighter version.); 1 medium Yellow Onion (Substitute with shallots for a milder taste.); 6 cups Sourdough Bread (Ensure it's stale or toasted for best texture.); 2 cups Gruyère Cheese (Can be replaced with Swiss cheese if necessary.); 1 cup Parmesan Cheese (Use Pecorino Romano as a substitute.); 8 large Eggs (No substitutions recommended.); 2 cups Whole Milk (Can use half-and-half for a richer flavor or almond milk for a dairy-free option.); 1 cup Heavy Cream (Can be replaced with evaporated milk for a lighter option.); 1 tablespoon Dijon Mustard (Omit if making a bland dish, but recommended for flavor.); to taste Salt; to taste Black Pepper; to taste Ground Nutmeg

The aroma of a home-cooked breakfast fills the air, instantly transporting me back to cozy mornings spent with family. Introducing Martha Stewart’s Make-Ahead Christmas Breakfast Casserole—a delightful dish that brings comfort and cheer to any festive gathering. This satisfying breakfast casserole layers savory pork sausage, nutty Gruyère cheese, and hearty sourdough bread in a rich egg custard, offering a make-ahead option that truly eases holiday stress. Not only does it serve a crowd, but the ease of preparation will leave you with more time to enjoy the festivities, rather than being stuck in the kitchen. As you watch this golden, puffed masterpiece emerge from the oven, you’ll find it hard to resist the allure of its creamy interior and slightly crispy top. Are you ready to impress your loved ones with a breakfast dish that’s as easy as it is delicious? Let’s get cooking!

Why is This Breakfast Casserole a Must-Try?

Unbeatable Convenience: Prepare it ahead, allowing you to relax on the big day.
Crowd-Pleaser: Perfect for hosting gatherings, serving 8-10 guests effortlessly.
Rich Flavors: The blend of savory sausage and creamy Gruyère cheese brings robust taste to every bite.
Textural Delight: Enjoy the contrast of crispy edges and a creamy middle that will keep everyone coming back for more!
Versatile Options: Swap in turkey sausage or add seasonal veggies for personal twists. Love pairing hearty breakfasts with fresh flavors? Try this casserole alongside my Baked Feta Eggs or a crispy Egg Cheese Croissant for a festive spread!

Breakfast Casserole Ingredients

For the Casserole

Pork Breakfast Sausage – Provides savory flavor and protein; swap with turkey sausage for a lighter version.
Yellow Onion – Adds sweetness and depth; substitute with shallots for a milder taste.
Sourdough Bread – Acts as the base for the casserole; ensure it’s stale or toasted for best texture.
Gruyère Cheese – Offers nutty flavors; can be replaced with Swiss cheese if necessary.
Parmesan Cheese – Enhances richness and adds a savory crust; use Pecorino Romano as a substitute.
Eggs – Creates the custard base that binds the casserole; no substitutions recommended.
Whole Milk – Adds creaminess; can use half-and-half for a richer flavor or almond milk for a lighter dairy-free option.
Heavy Cream – Improves richness; can replace with evaporated milk for a lighter option.
Dijon Mustard – Provides a hint of tang; omit if making a bland dish, but recommended for flavor.
Salt, Black Pepper, Ground Nutmeg – Essential seasonings; adjust to taste.

This breakfast casserole is sure to bring joy to your holiday mornings!

Step‑by‑Step Instructions for Martha Stewart’s Make-Ahead Christmas Breakfast Casserole

Step 1: Prepare Ingredients
In a large skillet, cook 1 pound of pork breakfast sausage over medium heat, breaking it into pieces. Once browned and fully cooked after about 8–10 minutes, add a finely chopped yellow onion. Sauté until the onion is translucent, approximately 5 minutes, then remove from heat and set aside to cool slightly before mixing with the other casserole ingredients.

Step 2: Assemble Casserole
In a spacious mixing bowl, combine the cooled sausage and onion mixture with 6 cups of cubed stale sourdough bread and 2 cups of shredded Gruyère cheese. Toss gently until the bread is evenly coated with the sausage and cheese mixture. This forms the flavorful base that will soak up the delicious custard in your breakfast casserole.

Step 3: Make Custard
In a separate bowl, whisk together 8 large eggs, 2 cups of whole milk, 1 cup of heavy cream, and 1 tablespoon of Dijon mustard until well combined and smooth. Season with 1 teaspoon of salt, 1/2 teaspoon of black pepper, and a pinch of ground nutmeg. This rich custard will bind the casserole and infuse it with flavor.

Step 4: Combine
Pour the creamy custard mixture over the bread, sausage, and cheese blend, using a spatula or wooden spoon to gently fold the ingredients together. Ensure all bread chunks are soaked with the custard for an even texture. You’ll notice the mixture becomes moist, which is essential for a well-textured breakfast casserole.

Step 5: Rest
Cover the bowl with plastic wrap and place it in the refrigerator for at least 2 hours or ideally overnight. This resting period allows the flavors to meld beautifully and the bread to absorb the custard, resulting in a satisfying breakfast casserole that’s ready to bake on Christmas morning.

Step 6: Bake
Preheat your oven to 350°F (175°C) before removing the casserole from the refrigerator. Uncover the dish and bake for 45–55 minutes until the top is golden brown and puffed. You’ll know it’s done when a knife inserted in the center comes out clean—the sight of that cheesy, bubbly goodness is truly irresistible.

Step 7: Serve
Once baked, let your delicious breakfast casserole cool for about 10 minutes before slicing. Serve warm, optionally garnished with fresh herbs for a festive touch. This Martha Stewart’s Make-Ahead Christmas Breakfast Casserole pairs perfectly with a light winter fruit salad or crispy bacon for an unforgettable holiday breakfast!

How to Store and Freeze Breakfast Casserole

Fridge: Store leftover breakfast casserole in an airtight container in the refrigerator for up to 3 days to maintain its freshness.

Freezer: For longer storage, freeze the casserole by wrapping it tightly in plastic wrap and then in foil. It can last up to 2 months in the freezer.

Reheating: To reheat, thaw overnight in the refrigerator if frozen. Bake in a preheated oven at 350°F until heated through, approximately 25-30 minutes.

Make-Ahead Tips: As a great make-ahead option, feel free to prepare the casserole a day in advance and store it in the refrigerator until ready to bake.

What to Serve with Martha Stewart’s Make-Ahead Christmas Breakfast Casserole?

Imagine the clinking of coffee cups, the warmth of fresh baked goods, and the joy of festive gatherings, all enhanced by a delightful spread.

Fresh Winter Fruit Salad: Brighten your plate with a colorful mix of seasonal fruits; the sweetness contrasts beautifully with the savory casserole.
Crispy Bacon: This classic breakfast favorite adds a smoky, crunchy element that pairs perfectly with the creamy texture of the casserole.
Simple Green Salad: Refreshing mixed greens with a light vinaigrette introduce a crisp, contrasting flavor to balance the richness of your dish.
Savory Herb Butter Biscuits: Light, flaky biscuits can be slathered with rich herb butter, enhancing the flavor experience at your breakfast table.
Warm Honey Butter: Serve this sweet and creamy topping alongside the casserole for a delightful addition that elevates every bite.
Sparkling Apple Cider: A fun and festive beverage option that pairs wonderfully with both sweet and savory flavors for a joyous morning.
Decadent Hot Chocolate: For a warming treat, serve velvety hot chocolate topped with whipped cream, adding a cozy touch to your holiday breakfast.
Homemade Cinnamon Rolls: Soft cinnamon rolls ooze with sweetness and spice, creating a heavenly duo with the casserole for those who enjoy classic treats.

Make Ahead Options

Preparing Martha Stewart’s Christmas Breakfast Casserole ahead of time is a game changer for busy holiday mornings! You can assemble the casserole up to 24 hours in advance by completing all steps up until the resting phase. After combining the ingredients, cover the dish tightly with plastic wrap and refrigerate overnight to allow flavors to meld while the bread absorbs the custard. This ensures that your breakfast casserole is just as delicious when baked. On Christmas morning, bake it straight from the refrigerator, adding a few extra minutes to the cooking time if needed. With this make-ahead option, you can enjoy more quality time with loved ones while still serving a warm, crowd-pleasing meal!

Breakfast Casserole Variations & Substitutions

Feel free to get creative and make this delightful casserole your own with these easy adjustments!

Vegetarian Option: Replace pork sausage with vegetarian sausage or sautéed mushrooms for a meatless delight. It adds an earthy flavor while keeping the heartiness intact.
Dairy-Free Delight: Use almond milk and a dairy-free cheese blend instead of milk and cheese to make this casserole suitable for lactose intolerance. It’ll still be creamy and delicious!
Herb Infusion: Incorporate fresh herbs like thyme or rosemary into the sausage mixture for an aromatic twist. The fragrant notes elevate the flavor profile beautifully.
Spicy Kick: Add diced jalapeños or a sprinkle of red pepper flakes to the custard for some heat. This touch brings a delightful warmth that excites the taste buds.
Extra Veggies: Toss in a handful of spinach, bell peppers, or zucchini for added nutrition and a colorful presentation. Veggies can add delightful textures and flavors that everyone will love.
Gluten-Free Swap: Use gluten-free bread to make a delicious alternative for those with gluten sensitivities. The casserole will still hold its wonderful flavors and textures.
Flavor Variations: Experiment with different cheeses, like cheddar or pepper jack, for unique flavor profiles. Each cheese adds its own delicious twist!
Fruit Surprise: Dried cranberries or chopped apples can be added to the mixture for a hint of sweetness, complementing the savory elements so beautifully.

To enrich your festive table, consider serving this casserole alongside my Baked Feta Eggs or a wonderful Egg Cheese Croissant for a well-rounded breakfast!

Expert Tips for Breakfast Casserole

Bread Selection: Use stale or toasted sourdough to prevent sogginess. Fresh bread can lead to a mushy texture that detracts from the casserole’s appeal.
Overnight Resting: Allow your casserole to rest overnight in the fridge. This step melds flavors and enhances the custard texture, making for a richer breakfast casserole.
Monitor Baking Time: Keep an eye on your casserole as it bakes. You want a golden top and puffed appearance, but avoid overcooking to maintain a creamy interior.
Customize Ingredients: Feel free to swap in turkey sausage or add seasonal veggies. This versatility ensures your breakfast casserole can cater to different tastes and dietary preferences.
Garnish for Flair: Add fresh herbs like parsley or chives right before serving. This simple touch not only elevates presentation but adds a burst of freshness to every bite.

Martha Stewart’s Make-Ahead Christmas Breakfast Casserole Recipe FAQs

What type of bread should I use for the casserole?
For the best texture, use stale or toasted sourdough bread. Fresh bread may create a mushy casserole, while stale or toasted pieces absorb the custard beautifully, providing that perfect custardy center.

How long can I store leftover breakfast casserole in the fridge?
Leftover breakfast casserole can be stored in an airtight container in the refrigerator for up to 3 days. Just make sure it cools completely before sealing it to maintain freshness!

Can I freeze the breakfast casserole?
Absolutely! To freeze, wrap the casserole tightly in plastic wrap followed by aluminum foil. This will protect it from freezer burn. You can store it for up to 2 months. When you’re ready to enjoy it, thaw overnight in the refrigerator before baking.

What if my casserole is too dry or soggy after baking?
If your casserole turns out dry, it might be due to overbaking or using too much stale bread, which can absorb too much moisture. On the flip side, if it’s too soggy, the bread may have been too fresh. For the future, ensure your bread is sufficiently stale, or reduce the baking time slightly!

Are there any dietary alternatives I can use in this recipe?
Certainly! For a lighter option, you can swap pork sausage with turkey sausage or even vegetarian sausage. Additionally, incorporating veggies like spinach or bell peppers can add nutrition and flavors while keeping it delicious and satisfying for everyone.