Sourdough Breakfast Casserole

Author: Emily

Published: 28 April 2026

Updated: 4 May 2026

Why make this recipe

Nothing says cozy quite like a warm, hearty casserole on a slow weekend morning. This Sourdough Breakfast Casserole is a delicious way to use up leftover bread, and it’s packed with protein from the eggs and sausage. Plus, it’s super versatile—great for both brunch gatherings and a simple, satisfying breakfast at home! You can prepare it the night before, which means less stress when it’s time to eat. Trust me, with its rich flavors and melty cheese, everyone will be asking for seconds!

How to make Sourdough Breakfast Casserole

Let’s get into it! You’ll need a few staple ingredients, and I bet you already have most of them at home. Here’s what you’ll need:

Ingredients:
6 eggs, 2 cups whole milk, 1 teaspoon salt, ½ teaspoon ground dry mustard, 6 slices sourdough bread (cut into 1” cubes), 1 pound breakfast sausage links (cooked and cut into 1” pieces or bacon), 1 ½ cups shredded cheese

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Now, let’s start cooking!

First, grab a very large bowl and whisk the eggs until all the yolks are broken. It’s a satisfying step, and the aroma will start to build as you whisk!
Next, pour in the milk, ground dry mustard, and salt. Give it another whisk to combine everything.
Now, add your cubed sourdough bread and cooked sausage or bacon into the mix. Stir it well, making sure all that lovely bread gets coated in the egg and milk mixture.
Time for the finishing touch! Fold in the shredded cheese until it’s all mixed up and looking delicious.
Grease a 9×13 baking dish with butter or avocado oil, and then pour your breakfast casserole mixture into the dish. Cover it and pop it in the fridge for at least 2 hours, or if you’re preparing ahead, let it sit overnight.
When you’re ready to bake, place the dish in a cold oven, and then heat it to 350ºF. This way, the casserole warms gradually.
Once your oven is preheated, set a timer for 35-45 minutes. Bake it until the center is set! If you like a soft texture, cover it with foil while baking. If crispy edges and a golden top are your thing, leave it uncovered.
After baking, let it cool for about 5 minutes before slicing and serving.

Now, doesn’t that sound comforting?

How to serve Sourdough Breakfast Casserole

This casserole shines on its own, but it’s also amazing with a side of fresh fruit or a simple green salad. I love serving this with some spicy homemade salsa for a little kick! Pairing it with a warm drink, like coffee or herbal tea, takes your breakfast vibe to the next level.

How to store Sourdough Breakfast Casserole

Got leftovers? No worries! Just keep any leftover casserole in an airtight container in the fridge. It’ll stay good for about 3-4 days. You can reheat it in the oven or microwave. Just be sure to cover it to keep it moist. If you’re feeling indulgent, you can even enjoy it cold—it’s that tasty!

Tips to make Sourdough Breakfast Casserole

Use day-old bread for a more textured casserole that hugs onto all the flavors.
Feel free to swap in any cooked meat you like; diced ham or crumbled bacon are both excellent choices! You could use baked salmon if you’re adventurous.
If you want to add vegetables, think spinach or peppers. Just sauté them first to release any excess moisture.

Variation

You can easily change this up with different cheeses or spices. Want a hint of spice? Try adding paprika or some diced jalapeños to the mix.

FAQs

Can I make this casserole ahead of time?
Absolutely! That’s the beauty of this recipe. You can prepare it the night before and let it sit in the fridge.

Can I freeze leftovers?
Yes! You can freeze portions of the casserole. Just make sure it’s tightly wrapped, and it should be good for about 1-2 months.

Can I use a different type of bread?
Of course! If you don’t have sourdough, any crusty bread will work. Just make sure it’s not too soft. I sometimes use whole wheat for a nuttier flavor.

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Conclusion

I hope you enjoy this Sourdough Breakfast Casserole as much as I do! It’s perfect for lazy mornings or for serving guests during holidays. Want to explore more delicious recipes? Check out this Sourdough Breakfast Casserole for inspiration on how to make it your own!

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