Sourdough Breakfast Casserole

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This healthy Sourdough Breakfast Casserole Recipe is packed full of vegetables, healthy fats, and protein. Made in a 9×13” pan it is great for a crowd or is an easy way to meal plan breakfasts for the week. Simply put it together the night before, bake in the morning, and you’re ready to feed the whole family! It is the perfect way to use up extra sourdough bread, or even better stale sourdough bread, and is easily customized based on what you have on hand. 

Sourdough egg casserole on a plate with berries

Breakfast casseroles are such an easy way to get a hearty breakfast on the table! All you need is a slice of the casserole and you have all the components of a nutritious, filling breakfast! My family loves to top this casserole with salsa or guacamole, but it also is just as tasty left plain. 

Why you’ll love this recipe

  • Customizable- make this with or without meat, add in your favorite veggies or whatever you have on hand, and top with your favorite toppings like salsa, hot sauce, or guacamole
  • Healthy and nutritious breakfast- this keeps you full for longer and is well-balanced with carbs, healthy fats, and protein. It’s a great way to get in a serving of veggies for breakfast.
  • Feeds a crowd- it’s a great option when feeding a crowd or for a smaller family make it once and you have breakfast taken care of for the week! 
  • Uses up stale sourdough bread- it’s always a bummer when sourdough bread goes stale but not to worry, with this recipe you give new life to hard sourdough bread. 
sourdough breakfast casserole with veggies and sourdough bread

Why use stale sourdough bread?

This recipe is a great use for sourdough bread going stale on your counter! When bread is stale, it starts to go hard, and while this isn’t ideal for something such as fresh sandwiches, using stale bread in this recipe absorbs more of the moisture from the eggs. However, using a fresh loaf of crusty, artisan sourdough bread works well too. If you use soft sourdough sandwich bread, cut the sourdough bread into cubes and add it to a sheet pan. Pop it into the oven at 350 degrees for a few minutes until the bread feels slightly hard.

Do I have to make this recipe the night before? 

Assembling the casserole the night before you bake it not only saves you time in the morning but also allows the bread to soak up all the flavor. Although you also could assemble and bake right away, I think you’ll love how easy it is to prep breakfast ahead of time! This is a great recipe to use for a Sunday morning brunch, breakfast for dinner, or to feed a crowd. 

Sourdough Breakfast Casserole Ingredients

Bread, eggs, cheese, milk and veggies for sourdough casserole
  • Sourdough bread – use artisan sourdough bread and cut it into cubes. 
  • Eggs- If you prefer a lower fat option you can swap out for 1 cup of egg whites.
  • Milk- Any type will work or you can even use a dairy-free alternative if needed. 
  • Shredded cheese- I like cheddar but feel free to use any type of shredded cheese you have on hand. 
  • Adobo Seasoning – this is optional but adds a great flavor
  • Garlic Salt
  • Everything but the bagel seasoning blend- this is optional but adds a great flavor
  • Yellow onion- You can finely chop or dice the onion depending on what you prefer. 
  • Veggies of choice- Use any veggie you have on hand or any combo you enjoy. For this recipe, I used red bell peppers, mushrooms, and spinach but tomatoes, broccoli, and/or asparagus would also be great. 

Optional add-ins

My favorite thing about this recipe is how versatile it is! You can make this a meatless breakfast and use only veggies, or you can add in any meat you’d like. Feel free to add in bacon crumbles, a package of cubed ham, or breakfast sausage. Just be sure to precook the meat before adding it to the casserole to ensure it is cooked through. 

How to Make the Sourdough Breakfast Casserole 

Bread sliced into cubes on a cutting board with a knife

To assemble the night before, cut your sourdough bread into cubes. You will need 6 cups of bread cubes, which is about half of a large loaf. If your bread is soft you can cut it into cubes add it to a sheet pan and then pop it into a 350-degree oven for a few minutes until the bread feels slightly hard. If you want to make fresh sourdough bread, use my simple sourdough recipe!

Chopped spinach, mushrooms, red bell pepper and onions

Next, dice up your onion and your choice of extra veggies. You will want about 2 cups of extra veggies. For this recipe, I used 1 cup of red bell pepper, ½ cup of mushrooms, and 1 cup of spinach. 

If you are choosing to add meat to your casserole, cook raw meat until cooked through. Or you can use leftover meat or one that is pre-cooked, such as ham. 

In a large bowl, add the eggs, milk and seasoning. Whisk to combine together. Then add in half the cheese, veggies, optional add-ins, and bread cubes. Stir to combine everything. 

Closeup of uncooked sourdough casserole

Spray a 9×13 pan with cooking oil and place the mixture in the dish. Add the second half of the cheese on top. 

If you assembled the casserole the night before, cover the unbaked casserole and sit in the fridge overnight. You can leave the casserole unbaked in the fridge for up to 24 hours. This gives the bread time to soak up the liquid and flavor and is worth the wait!

The next morning, preheat the oven to 350 degrees Fahrenheit. Add the casserole to the hot oven and bake for 50 minutes or until the egg mixture is cooked through.

Close up on baked sourdough casserole

To serve, remove from oven and let it sit for 5 minutes. Then slice it into 8 slices and serve. The casserole is filling and great served on its own, or you can pair it with a side of fresh fruit. 

Optional toppings

Get creative and add some toppings to the casserole! My favorite is guacamole and salsa, or hot sauce would be great as well! You could also top it with fresh herbs such as chives, parsley, or cilantro. 

Sourdough egg casserole on a plate with spoon and fork

How to store

Store the sourdough breakfast casserole in an airtight container in the fridge for up to 3-4 days. This is a great recipe to use for meal prep and have breakfast ready throughout the week! You can reheat in the microwave or pop into the oven at 350 degrees until it has heated through. 

More sourdough breakfast recipes

Fluffy Sourdough Pancakes

Sourdough Oatmeal Bran Muffins 

Crunchy Sourdough Granola (add to yogurt!)

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Close up on baked sourdough casserole

Sourdough Breakfast Casserole

Yield: 8 servings
Prep Time: 15 minutes
Cook Time: 50 minutes
Total Time: 1 hour 5 minutes

If you’re looking for a healthy and nutritious breakfast casserole made with sourdough bread, eggs, vegetables, and cheese look no further. This hearty overnight egg bake is a crowd pleaser! Easy to customize with your favorite veggies, and can be made meatless or add in bacon, sausage, or ham for extra protein. This sourdough breakfast casserole is quick and easy to put together and makes for a filling and delicious breakfast.


  • 6 cups sourdough bread cubed (about ½ loaf of sourdough bread)
  • 9 large eggs
  • 2 cups milk
  • 1 cup shredded cheese
  • 1 tsp Adobo seasoning (optional)
  • 1 tsp garlic salt
  • 1 Tbsp Everything But The Bagel Seasoning
  • 2 cups veggies of choice (I do 1 cup red bell pepper, ½ cup mushroom, 1 cup spinach)
  • ½ large yellow onion


  1. Cube sourdough bread.
  2. Dice 2 cups of veggies and 1/2 an onion.
  3. In a large bowl mix eggs, milk, half the cheese, and seasonings.
  4. Add in the veggies and bread into the mixture. 
  5. Spray 9x13 pan and place the mixture in the pan. Add the remaining cheese on top. 
  6. Cover and let sit in the fridge ideally overnight (up to 24 hours). 
  7. Bake the next morning at 350F for 50 mins.


This recipe can be made the night before and cooked the next morning, or if you are short on time you can assemble and bake right away.

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Nutrition Information:
Yield: 8 Serving Size: 1
Amount Per Serving: Calories: 276Total Fat: 12gSaturated Fat: 5gTrans Fat: 0gUnsaturated Fat: 6gCholesterol: 228mgSodium: 707mgCarbohydrates: 25gFiber: 2gSugar: 6gProtein: 17g

The nutritional information provided is an estimate from third-party calculations.

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