Table of Contents

• Reasons to Love This Make-Ahead Sourdough Breakfast Casserole
• Key Ingredients for Your Sourdough Breakfast Casserole
• How to Prepare This Easy Sourdough Breakfast Casserole
• Expert Tips & Delicious Variations
• Perfect Serving Suggestions for Brunch
• Storing and Reheating Your Sourdough Casserole Leftovers
• More Irresistible Overnight Casseroles to Explore
• Sourdough Breakfast Casserole Recipe Card

Reasons to Love This Make-Ahead Sourdough Breakfast Casserole

• Effortless Make-Ahead Convenience: The true genius of this sourdough breakfast casserole lies in its overnight preparation. If you’re hosting company for brunch, planning a leisurely weekend, or simply want to simplify your mornings, this recipe is your answer. Assemble all the ingredients the night before, cover it, and let it chill in the refrigerator. The next day, just pop it in the oven, and within minutes, you’ll have a warm, bubbling, and delicious breakfast ready to serve. This frees up precious morning time, allowing you to relax or socialize rather than being stuck in the kitchen.
• Irresistibly Fluffy Sourdough Bread Chunks: While I often gravitate towards hash brown breakfast casseroles with potatoes as the base, I decided to shake things up with bread this time – and sourdough is an absolute game-changer! Its distinct tangy flavor and robust texture are perfect for soaking up the creamy egg mixture without becoming mushy. This makes it an ideal way to utilize any leftover or slightly stale sourdough loaf. Each bite offers soft, fluffy, and flavor-soaked bread chunks, making this casserole incredibly satisfying and wonderfully filling. It’s a texture sensation that truly elevates the dish.
• Perfect for Any Occasion: This versatile breakfast casserole recipe is incredibly adaptable, making it ideal for feeding a crowd, no matter the event. Whether it’s a festive holiday breakfast, a casual weekend brunch, a potluck, or even a special gathering, this dish is always a hit. I once prepared this breakfast casserole for my son’s teachers’ appreciation lunch, and received numerous emails afterward certifying its overwhelming success. What’s not to love about the irresistible combination of fluffy bread and eggs, perfectly melted cheese, and savory sausage? It’s comfort food at its finest, guaranteed to please any palate.

Key Ingredients for Your Sourdough Breakfast Casserole

This Sourdough Breakfast Casserole is not only a fantastic way to give new life to older sourdough bread, but it’s also a superb recipe for utilizing an abundance of eggs. Each ingredient plays a crucial role in creating the rich, savory flavors and comforting textures of this dish. Below are some detailed notes on the ingredients you’ll need, along with useful tips for substitutions and enhancements. For the precise measurements and complete instructions, please scroll down to the printable recipe card.

How to Prepare This Easy Sourdough Breakfast Casserole

I truly love hosting, but the last thing I want is to be jolted awake at 6 AM to prepare a full breakfast spread for a house full of hungry guests. And, let’s be honest, a house full of people probably doesn’t want to encounter me before my first cup of coffee! I am many things, but an early riser is definitively not one of them. This is precisely why this sourdough breakfast bake holds a special place in my heart – it’s a dream come true for effortless entertaining.

The beauty of this recipe is its simple, straightforward preparation that you can do the night before. Follow these quick steps to assemble your delicious make-ahead breakfast:

• Cook the Sausage: Begin by breaking up and browning your chosen breakfast sausage in a large, hot skillet. Cook until it’s fully cooked through and wonderfully caramelized. Once done, make sure to drain any excess grease thoroughly. This step is crucial for preventing a greasy casserole and ensuring a clean, savory flavor. Set the cooked sausage aside.
• Assemble the Casserole Layers: In a separate large bowl, whisk together the eggs, Dijon mustard, and milk until they are well combined and a smooth, creamy mixture forms. Now, prepare your baking dish. Spread about half of your sourdough bread cubes evenly across the bottom of a greased 13×9 inch casserole dish. Sprinkle half a cup of shredded cheese over the bread, followed by an even layer of the cooked sausage. Carefully pour the egg mixture evenly over these layers, ensuring it starts to seep down. Finally, add the remaining bread cubes and cheese on top. Gently press everything down into the egg mixture to ensure the bread is fully soaked, which is key for those fluffy, flavor-infused chunks.

• Refrigerate Overnight: Once assembled, tightly cover the casserole dish with plastic wrap or aluminum foil. Place it in the refrigerator and let it chill overnight (or for at least 8 hours). This crucial step allows the sourdough bread to fully absorb the egg mixture, developing a deeper flavor and ensuring a wonderfully custardy texture when baked. Before you plan to bake it the next morning, remember to remove it from the fridge and let it sit at room temperature for about 30 minutes to an hour. This helps it bake more evenly.
• Bake to Perfection: Preheat your oven to 350ºF (175ºC). Place the casserole in the preheated oven and bake for approximately 45-55 minutes. The casserole is perfectly cooked when it’s golden brown on top, puffed up, and a knife inserted into the center comes out clean, without any wet, eggy streaks. The cheese should be bubbly and beautifully melted, and the edges slightly crispy. Let it rest for a few minutes before serving to allow it to set.

Expert Tips & Delicious Variations for Your Sourdough Breakfast Casserole

• Quickly Stale Your Bread: The success of this recipe heavily relies on using bread that’s a few days old, as it optimally soaks up the egg mixture without becoming overly mushy. If you don’t have stale sourdough readily available, don’t fret! You can easily stale it yourself. Simply cut your fresh sourdough into cubes and spread them out in a single layer on a baking sheet. Lightly toast them in a 300ºF (150ºC) oven for about 10-15 minutes, or until they are dried out but not browned. This crucial step prevents a soggy casserole base.
• Experiment with Different Proteins: While breakfast sausage is a classic choice, feel free to get creative with other proteins. As mentioned in the Ingredients section, you can swap it for other ground sausages like spicy chorizo or savory Italian sausage to introduce new flavor dimensions. For a different twist, consider adding diced cooked ham, crispy bacon (cooked and crumbled), or even a combination of different meats. For a meat-free alternative, crumbled plant-based mince or seasoned crumbled tofu (similar to what I use in my tofu tacos) can provide a delicious and satisfying option.
• Boost with Fresh Vegetables: Incorporating vegetables not only adds nutrients and color but also introduces new textures and flavors. Love sautéed mushrooms? Add them! You can also bulk up this sourdough breakfast casserole with diced and sautéed bell peppers (any color), sweet caramelized onions, or a handful of fresh greens like spinach or kale. Just make sure to sauté tougher vegetables beforehand to ensure they are tender in the baked casserole, and wilt greens to remove excess moisture.
• Add a Spicy Kick: If you enjoy a bit of heat to wake up your palate, there are several ways to spice up this casserole. Swap out some of the cheddar for shredded Pepper Jack cheese for a mild, creamy heat. For a more pronounced kick, mix in fresh or pickled jalapeños (deseeded for less heat). Alternatively, a sprinkle of red chili flakes stirred into the egg mixture or over the top before baking will add a pleasant warmth. A dash of your favorite hot sauce on individual servings is also a great option.
• Cheese Blend Brilliance: Don’t limit yourself to a single cheese! A blend of cheeses can add complexity. Try combining sharp cheddar with a milder Monterey Jack, or even a smoked gouda for a deeper, richer flavor. Different cheeses melt at different rates, contributing to a wonderfully varied texture.
• Herbaceous Freshness: Fresh herbs can significantly brighten the flavor profile. Chop some fresh chives, parsley, or even a little rosemary or thyme and sprinkle them into the egg mixture or over the top before baking. They add a fresh, aromatic counterpoint to the savory components.

Perfect Serving Suggestions for Brunch

This sourdough breakfast casserole is a wonderfully complete meal on its own, packed with protein, carbs, and delicious flavors. However, if you’re catering to a hungry brunch crowd or simply want to elevate your spread, I often accompany it with a few easy and complementary sides. These additions create a well-rounded and impressive meal without adding much extra effort:

• Classic Sides: For a hearty American brunch, consider serving warm and savory baked beans alongside the casserole. The rich, sweet-and-savory profile of the beans perfectly complements the eggy, cheesy casserole.
• Fresh Fruit Salad: To add a refreshing contrast, a vibrant berry fruit salad is always a welcome addition. The sweetness and acidity of fresh berries cut through the richness of the casserole, providing a light and healthy balance. Think mixed berries, melon, and grapes for a colorful array.
• Beverage Pairings: No brunch is complete without the right drinks! For the adults, effervescent raspberry mimosas or classic orange juice and champagne are always a hit. For the kids and non-alcoholic options, a homemade Orange Julius provides a creamy, frothy, and delicious treat that feels special. Coffee, tea, and fresh juices are, of course, always essential.
• Light Green Salad: A simple mixed green salad with a light vinaigrette can also be a lovely, fresh addition, offering a crisp texture and a touch of vibrancy to the plate.

Storing and Reheating Your Sourdough Casserole Leftovers

One of the many benefits of this hearty sourdough breakfast casserole is how well it stores and reheats, making it perfect for meal prepping or enjoying throughout the week. Don’t let any delicious leftovers go to waste!

• Refrigerate: To keep your leftover breakfast casserole fresh, allow it to cool completely after baking. Then, transfer it to an airtight container or cover the baking dish tightly with plastic wrap or aluminum foil. Stored properly in the refrigerator, it will remain delicious for up to 3 days. This makes it an excellent option for quick breakfasts or lunches during busy weekdays.
• Reheat: When you’re ready to enjoy your leftovers, you have a couple of options. To reheat the entire casserole, cover it loosely with foil to prevent drying out and warm it in a 350ºF (175ºC) oven until heated through, typically around 20-30 minutes. For individual servings, the microwave is your best friend! Place a slice on a microwave-safe plate and heat in 30-60 second intervals until warm, ensuring even heating.
• Freeze: This casserole also freezes beautifully, making it perfect for long-term storage or preparing ahead for future meals. Once the casserole has fully cooled, wrap it tightly in a double layer of plastic wrap, followed by a layer of aluminum foil. You can freeze the entire casserole or slice it into individual portions before wrapping for convenient grab-and-go meals. Store in the freezer for up to 2 months. To reheat from frozen, you can either thaw the casserole in the refrigerator overnight before warming it in the oven, or bake it directly from frozen (this will significantly increase baking time, often requiring an hour or more at 350ºF, covered, until heated through).

More Irresistible Overnight Casseroles to Explore

If you’ve fallen in love with the convenience and deliciousness of make-ahead breakfast casseroles, you’re in luck! There’s a whole world of overnight delights waiting to be discovered. These recipes are perfect for stress-free entertaining or simply making your mornings a little easier. Explore some of my other favorite recipes:

• Croissant Baked French Toast: A decadent and buttery twist on classic French toast, perfect for a luxurious brunch.
• Chocolate French Toast Bake: Indulge your sweet tooth with this rich and comforting breakfast casserole, ideal for chocolate lovers.
• Ham and Potato Casserole: A savory and filling option featuring hearty potatoes and delicious ham, excellent for a complete meal.
• Breakfast Enchiladas: A fun and flavorful Mexican-inspired breakfast, packed with eggs, cheese, and your favorite fillings.
• Blueberry Breakfast Cake: A sweet and fruity bake that feels like dessert but is perfectly acceptable for breakfast or brunch.