Larissa and I adore casseroles because they’re so easy to make and, depending on the casserole, can give us plenty of leftovers to enjoy during the week.
This vegetarian breakfast casserole is simple to prepare. Saute the vegetables, combine the egg mixture, toss everything into a casserole dish, and pop it into the oven. The result is a hearty breakfast packed with hash browns, bell peppers, eggs, and cheesy goodness.
This vegetarian egg casserole is simple, flexible, and perfect when you want something warm, filling, and easy to reheat later. It works just as well for a lazy Sunday brunch as it does for a holiday breakfast like Christmas morning. The base of shredded hash browns and the fluffy egg mixture make it satisfying, while colorful vegetables like red bell peppers and green onions add flavor and texture.
You can keep it classic with cheddar cheese or tweak it with dairy free ingredients for a vegan breakfast casserole variation.
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What Makes This Vegetarian Breakfast Casserole Recipe Special
One of the best things about this vegetable lover’s breakfast casserole is how adaptable it is. You can grab frozen shredded hashbrowns from the grocery store, add your favorite mixed veggies, and still end up with a dish that tastes like it took a lot more effort than it actually did.
The combination of shredded potatoes and fluffy eggs creates a hearty base, while sautéed vegetables like bell peppers and onions add flavor without overpowering the dish. A sprinkle of shredded cheese melts into the casserole as it bakes, creating an irresistible layer of cheesy goodness.
It’s also a great make-ahead breakfast. Assemble everything the night before, cover the casserole dish with plastic wrap, and bake it in the morning. That’s one less thing to worry about when you’re hosting brunch or feeding hungry guests during the holidays.
Shopping List
- frozen shredded hashbrowns
- olive oil
- red bell peppers
- green bell peppers
- green onions
- sweet potatoes (optional)
- garlic powder
- onion powder
- red pepper flakes (optional)
- eggs
- almond milk or other non dairy milk
- sour cream
- cheddar cheese
- nutritional yeast (optional)
- salt and pepper
- olive oil spray
Instructions
Prepare the oven and baking dish
Preheat oven to 375°F. Lightly coat a 9×13 inch glass baking dish or other oven-safe dish with olive oil spray.
Cook the vegetables
Heat olive oil in a non-stick skillet or cast-iron pan over medium heat. Add the bell peppers, sweet potatoes, and green onions. Cook for about 5 minutes until the vegetables soften slightly.
Prepare the hash brown layer
Spread the frozen shredded hashbrowns evenly across the prepared casserole dish. Sprinkle the cooked vegetables over the top.
Mix the egg mixture
In a large bowl, whisk together eggs, almond milk, sour cream, garlic powder, onion powder, nutritional yeast, salt, and pepper until fully combined.
Assemble the casserole
Pour the egg mixture evenly over the hash browns and vegetables. Sprinkle shredded cheddar cheese across the top.
Bake the casserole
Place the baking dish in the preheated oven and bake for 35 to 40 minutes until the egg casserole is fully set and the cheese is golden.
Rest and serve
Allow the vegetarian breakfast casserole to rest for about 5 minutes before slicing. This helps the casserole hold its shape when serving.
Why This Vegetarian Breakfast Casserole Recipe Works
The key to a great breakfast casserole is balance. The shredded hash browns create a sturdy base that holds everything together, while the egg mixture binds the vegetables and cheese into a soft, fluffy texture.
Cooking the vegetables first removes excess moisture, which prevents the casserole from turning watery. It also deepens the flavor of the bell peppers and onions.
Using a combination of eggs, milk, and sour cream keeps the casserole rich without being heavy. The result is a dish that reheats beautifully, so leftover slices are just as satisfying the next day.
Variations to Try
Make it vegan Swap the eggs with a tofu egg mixture or a plant-based liquid egg substitute. Use dairy-free cheese and non-dairy milk to create a vegan breakfast casserole.
Add Mediterranean ingredients Toss in artichoke hearts, kalamata olives, and fresh herbs like parsley or oregano for a Mediterranean inspired version.
Go gluten free This recipe is naturally gluten free as long as your frozen shredded hashbrowns are certified gluten free.
Boost the veggies Add mushrooms, spinach, or other mixed veggies for an even more colorful vegetable lover’s breakfast casserole.
Try breakfast potato cubes If you prefer more texture, replace the shredded hash browns with small roasted potato cubes.
Tips to Keep It Fresh
A good breakfast casserole should be just as enjoyable the next day. Store leftover slices in an airtight container in the refrigerator for up to four days. When you want to reheat slices, warm them in the oven or microwave until heated through.
This casserole also freezes well. Wrap individual slices in plastic wrap and place them in a freezer-safe container. They make an easy breakfast option for busy mornings.
If you’re preparing this for a holiday breakfast, you can assemble everything the night before. Cover the casserole dish with plastic wrap and store it in the refrigerator overnight. In the morning, simply remove the wrap and bake.
For extra flavor, consider finishing the casserole with chopped fresh herbs or a sprinkle of nutritional yeast just before serving.
Vegetarian Breakfast Casserole
Equipment
- 9×13 baking dish
- Mixing bowl
- Whisk
- non-stick skillet or cast-iron pan
Ingredients
- 3 cups frozen shredded hashbrowns
- 1 tablespoon olive oil
- 1/2 cup diced red bell peppers
- 1/2 cup diced green bell peppers
- 1/3 cup sliced green onions
- 1/2 cup diced peeled sweet potatoes optional
- 1 teaspoon garlic powder
- 1 teaspoon onion powder
- 1/2 teaspoon red pepper flakes optional
- 8 large eggs
- 1/2 cup almond milk or other non dairy milk
- 1/2 cup sour cream
- 1 1/2 cups shredded cheddar cheese
- 1/4 cup nutritional yeast optional
- salt and pepper to taste
- olive oil spray for baking dish
Instructions
- Preheat oven to 375°F and coat a 9×13 inch baking dish with olive oil spray.
- Heat olive oil in a skillet over medium heat and cook bell peppers, sweet potatoes (if using), and green onions for about 5 minutes until slightly softened.
- Spread frozen shredded hashbrowns evenly in the prepared baking dish.
- Add the cooked vegetables evenly over the hash browns.
- In a large bowl whisk together eggs, almond milk, sour cream, garlic powder, onion powder, nutritional yeast, salt, and pepper.
- Pour the egg mixture over the hash browns and vegetables.
- Sprinkle shredded cheddar cheese evenly across the top.
- Bake for 35 to 40 minutes until the casserole is fully set and lightly golden.
- Let the casserole rest for 5 minutes before slicing and serving.
This vegetarian breakfast casserole is great for busy weekdays, weekend brunch, or a relaxed holiday breakfast. It’s hearty, simple to prepare, and flexible enough to adapt with whatever vegetables you have in the fridge. Once you make it, don’t be surprised if it becomes a regular part of your breakfast rotation.
Love this recipe? Check out our full collection of vegetarian and vegan recipes for more delicious ideas! And if you’re looking to share your creations (or get inspired by someone else’s), join our closed Facebook Group, The Peas and Carrots Society, a group of non-judgy folks who welcome all! Nothing but good food, good friends, and good fun!
FAQs
Can you make vegetarian breakfast casserole ahead of time?
Yes. Assemble the casserole the night before, cover it tightly with plastic wrap, and store it in the refrigerator. Bake it the next morning according to the recipe instructions.
Can you freeze breakfast casserole?
Breakfast casserole freezes well. After baking, let it cool completely, slice it into portions, wrap them individually, and freeze for up to two months.
What vegetables work best in a breakfast casserole?
Bell peppers, onions, spinach, mushrooms, broccoli, and sweet potatoes all work well. Just cook watery vegetables first so they don’t release too much moisture during baking.
How do you know when an egg casserole is done?
The casserole is finished when the center is set and no longer jiggly. A knife inserted into the center should come out clean.
How do you reheat breakfast casserole?
Reheat slices in the microwave for quick meals or warm them in the oven at 350°F until heated through for the best texture.
