Sourdough Breakfast Casserole

When you want the ultimate breakfast casserole, look no further than this sourdough breakfast casserole.

It’s loaded with sourdough bread, eggs, Greek yogurt, sausage, kale, and Gruyere for a make-ahead meal that will make everyone clamor for more!

How to make sourdough breakfast casserole

Featured Ingredients

• Olive oil: This gives the strata a nice rich base of flavor.
  • But, you could also use extra-virgin olive oil to sauté the vegetables for that rich olive oil flavor.
• Yellow onion: We really like yellow onions in this sourdough breakfat casserole. But, if you only have red or white onions, they’d work as well.
  • Also, if you have leeks on hand, they’d bring a beautiful and delicate flavor to the dish.
• Breakfast sausage: Any type of breakfast sausage would be great in this breakfast casserole! We enjoy sausage with hints of rosemary, sage, and black pepper.
  • But, you could really get creative here.
  • You can grab brands that incorporate a little sweetness and spice, like a chicken apple jalapeno or you could even use a “Beyond” type of sausage that’s plant-based as opposed to one made with pork.
  • Any type of sausage that’s your favorite will work really well here!
• Kale or spinach: A good hearty kale is really great in this strata! It adds body and holds up well to the cubed sourdough.
  • However, peppery arugula or mustard greens would be wonderful if you have some on hand.
  • And of course, delicate spinach would be a delight after being sautéed with the other veggies.
• Gruyere: The rich, creamy, salty, and nutty flavor of gruyere really brings a pop of flavor to this strata!
  • If you’ve never experienced the joy that is gruyere, just think of it as Swiss cheese’s elegant cousin in a metaphorical cummerbund.
  • However, if you don’t have any gruyere on hand, a good gouda will pitch hit really nicely.
• Eggs: We always recommend local or organic eggs in our recipes.
  • Because the hens eat a varied diet, that means that the eggs have less cholesterol and more flavor.
• Milk: We used standard cow’s milk in this breakfast casserole.
  • But, if you really wanted to make it over-the-top decadent, you could substitute the milk with half and half, whipping cream, or heavy cream.
• Greek yogurt: Thick, luscious, and full of tang, Greek yogurt really rounds out the flavors in this dish.
  • Also, it gives the casserole even more body (if that’s possible!) along with a creamy and luscious texture.
• Sourdough bread: Or your favorite loaf!

Step-by-Step Instructions

1. Preheat oven to 350 degrees. Coat a 9x13 baking dish with cooking spray. Set aside.
2. In a large skillet, heat olive oil to medium heat.
3. Add onion and saute 3-4 minutes, until just starting to soften.
4. Add breakfast sausage and cook, breaking up into pieces with a wooden spoon, until almost all browned, about 6-7 minutes.
5. Stir in greens, roasted red pepper (optional) and garlic and saute another 2-3 minutes, until greens are wilted.
6. In an extra-large mixing bowl, whisk together eggs, milk, Greek yogurt, Dijon, salt, black pepper and red pepper flakes.
7. Add sourdough bread cubes, sausage mixture and diced cheese to the bowl and toss to combine. Transfer to the greased baking dish and spread out evenly.
8. Bake 35-45 minutes, until set and knife inserted into the center comes out clean.
9. Slice and serve.

Recipe Substitutions and Alterations

• Instead of sourdough: Use any whole grain loaf of bread that is hearty and thick. Fluffy bakery bread is the best here!
• Instead of sausage: Try any breakfast sausage or plant-based sausage, or leave it out of the recipe.
• Instead of Gruyere: Try sharp white cheddar or gouda.
• Add veggies: This is the type of dish that lends itself to all kinds of veggie love. You could add mushrooms, asparagus, broccoli, or even cooked pearl onions to this meal.
• Add herbs: While we mainly used salt, pepper, and red pepper flakes in this breakfast casserole, you could also use this as a playground for fresh herbs from the fall garden!
  • Woodsy herbs like rosemary and thyme would make a fantastic flavor bomb to an already flavorful dish!

Nutrition Considerations

• To make this gluten free: Use gluten free bread. Be sure all other packaged ingredients are gluten free.
• To make this dairy free: Use a dairy free milk and cheese for this recipe. Be sure all other ingredients are gluten free.
• To make this vegetarian: Omit the sausage or use plant-based sausage.
• To make this nut free: This recipe is nut free. Be sure all packaged ingredients are nut free.

Can I make ahead and freeze this breakfast casserole?

To make-ahead:

• You can prep this breakfast casserole, cover it with plastic wrap and store it in the refrigerator overnight.
• It'll last a day or two in the fridge before it needs to be baked.

To freeze and reheat:

• Once the casserole is baked, let it cool, then wrap with aluminum foil and freeze it up to 2 months.
• Let it thaw in the refrigerator, then bake it again at 350 degrees F until just heated through.
• I recommend baking and freezing it in an aluminum disposal baking dish.

To store and reheat:

• Once the casserole is baked, cut it into squares and transfer to airtight, microwave-safe containers.
• Reheat in the microwave 1-2 minutes or until heated through.
• It can be stored in the refrigerator up to 5 days.

Fabulous breakfast recipes:

• Asparagus & Sausage Quiche
• Broccoli Cheese Egg Muffins
• Chorizo & Hash Brown Egg Muffins
• Cauliflower Waffle Breakfast Sandwich
• Copycat Starbucks Egg Bites

Sourdough Breakfast Casserole

Print Recipe

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A delicious breakfast casserole made with sourdough bread, eggs, yogurt, sausage, kale and roasted red peppers. It can be made in advance as a meal prep idea or the day of! 

• Author: Julie Andrews
• Prep Time: 15-20 mins
• Cook Time: 45-55 mins
• Total Time: 1 hr-1 hr 15 mins
• Yield: 12 Servings 1x
• Category: Breakfast
• Method: Stove-Top, Baking
• Cuisine: American

Ingredients

Units USM Scale 1x2x3x

• 1 tablespoon olive oil
• ½ medium yellow onion, peeled and diced
• 1-pound all-natural breakfast sausage
• 3 cups chopped kale or spinach (any green)
• 2 roasted red peppers, chopped (optional)
• 3 cloves garlic, peeled and minced
• 4-ounces Gruyere or gouda cheese, diced
• 10 large eggs
• 1 cup milk
• ⅔ cup plain Greek yogurt
• 2 tablespoons Dijon mustard
• 1 ½ teaspoons coarse salt
• ½ teaspoon ground black pepper
• ¼ teaspoon crushed red pepper flakes
• 1-pound loaf sourdough bread, cubed (about 8-9 cups)

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Instructions

1. Preheat oven to 350 degrees. Coat a 9x13 baking dish with cooking spray. Set aside.
2. In a large skillet, heat olive oil to medium heat. Add onion and saute 3-4 minutes, until just starting to soften. Add breakfast sausage and cook, breaking up into pieces with a wooden spoon, until almost all browned, about 6-7 minutes. Stir in greens, roasted red pepper (optional) and garlic and saute another 2-3 minutes, until greens are wilted.
3. In an extra-large mixing bowl, whisk together eggs, milk, Greek yogurt, Dijon, salt, black pepper and red pepper flakes. Add sourdough bread cubes, sausage mixture and diced cheese to the bowl and toss to combine. Transfer to the greased baking dish and spread out evenly.
4. Bake 35-45 minutes, until set and knife inserted into the center comes out clean. Slice and serve.

Notes

Substitution Tip: Use whole grain bread instead of sourdough.

Nutrition

• Serving Size: 1/12 of recipe
• Calories: 376
• Sugar: 2g
• Sodium: 535mg
• Fat: 22g
• Saturated Fat: 6g
• Unsaturated Fat: 16g
• Trans Fat: 0g
• Carbohydrates: 21g
• Fiber: 1g
• Protein: 23g
• Cholesterol: 208mg