Make this easy hashbrown breakfast casserole with spinach, red bell peppers, and onions for a veggie-packed start to the day!
This vegetarian hashbrown spinach egg casserole is perfect for your Christmas morning or holiday breakfast! With plenty of vegetables and room for even more, it’s an easy plant-forward breakfast recipe that can be made ahead.
But if you’re in the mood for something sweeter, you have to also try my sheet pan french toast recipe. Maybe make both for your brunch table?
The assembly is quick and baking is mostly hands-off.
Here’s what’s you’ll need
Frozen shredded hashbrowns
Red bell pepper
Salt and pepper
Olive oil spray
Serve this egg bake for breakfast. Or make it for lunch or dinner with a green salad. I love serving it with a simple arugula salad dressed with olive oil and red vinegar.
Frozen hashbrowns. I used plain frozen shredded hash browns and didn’t unthaw them. You can also use seasoned hashbrowns – just adjust the seasonings to taste. But do keep in mind that most packaged hashbrowns have a considerable amount of salt added. Adjust the salt you add based on the potatoes you buy.
Spinach. I like using spinach or any quick-cooking green in this recipe. I recommend steaming fresh spinach either on top of the stove or in the microwave. You can also use frozen spinach. Be sure to thaw and drain it completely before adding to the casserole. You don’t have to heat it up or steam it.
Bell peppers. Feel free to swap in any bell pepper. I like the red bell pepper for the color and hint of sweetness but other colors work great.
Can this recipe be made vegan?
Yes. You can make this into a vegan breakfast casserole with two changes.
Use plant-based liquid egg substitute for the eggs. Products like JUST Egg or Zero Egg are the most popular options and there are also store brands. Follow the guidelines on the package to pour the equivalent to 8 eggs (or 4 if you’re splitting the recipe).
The flavor and texture will change. You will need to adjust the salt down since these products already have salt in them. And most liquid vegan eggs require a bit more time to cook so you’ll probably need to cook the casserole longer to set.
Omit the cheese or swap for your favorite non-dairy cheese. I am not a huge fan of vegan cheeses – just haven’t found one that I personally love. But you get to make the casserole how you like it. If you enjoy vegan cheese – go for it in the same quantity.
Making the casserole ahead
Refrigerate the egg bake overnight. Bake at 350 F for 60-75 minutes or until cooked through.
Got leftovers? Reheat in the oven or toaster oven at 350 for 15 minutes. You can also microwave each slice on medium heat for about 1 minute until heated through, reaching an internal temperature of 165F.
You can also make these Spinach Egg and Cheese Breakfast Sandwiches ahead of time! And for more veggie-forward recipes, be sure to grab a copy of my cookbook, The Plant Love Kitchen wherever books are sold!
Vegetarian Hashbrown Breakfast Casserole
- 1 20 ounce bag frozen shredded hashbrowns
- ½ cup sweet onion, diced
- 1 medium red bell pepper, diced
- 5 ounces spinach, steamed
- 8 large eggs
- 1 ⅓ cup milk
- 1 teaspoon garlic powder
- 1 teaspoon coarse salt
- ½ teaspoon black pepper
- 1 cup shredded cheddar cheese, divided
- olive oil spray
- Preheat oven to 350 F.
- Layer the hashbrowns, red bell pepper, onion, and spinach and half the cheese (if using) in a 9 x 13 inch casserole dish.
- Whisk the eggs, milk, garlic powder, salt, and pepper in a bowl. Pour evenly over vegetable mixture. Top with the rest of the cheese (if using).
- Bake 50 – 60 minutes, until the center is cooked through and the cheese is golden (if using). Serve warm.
Is it okay to refrigerate this overnight two nights before baking?
Hi Linda, Per food safety guidelines, you can keep the unbaked casserole in the refrigerator up to 2 days.
This was disappointing. The hash browns became mealy and it was just all a bit bland. It is very light, though. If one wants a light, low calorie egg casserole, it is that. The only change I made from the recipe was to saute the onions and peppers first. My suggestion is to use whole milk and a bit more salt & seasonings. Maybe add some herbs.
Thanks for sharing, Deborah.
I thought this recipe was great. I tweaked it a bit with the veggies (I only used eggs, frozen hashbrowns, milk, spinach, cheese, salt and pepper because I have bad acid reflux). It turned out delicious and I think this is a great guide for a hashbrown egg bake. Thank you.
I’m so glad you enjoyed it Ashley. Thanks for taking the time to share how you tweaked the recipe!
Can you make this casserole the night before and cook it in the morning?
Absolutely! I’d keep it for only one night. It’s perfect for making ahead.
I’ve made this casserole for my mom after she was diagnosed with cancer. My 2 sisters & GF decided to pop up for brunch that day, and now they want me to make this ALL the time.
I can’t tell from the picture if this is for an 8 x 8 or a 9 x 13 casserole. I am trying to find a dish for a church Lenten meal and need something that will feed a lot, making many of the same casserole. Thanks in advance.
It’s 9×13. Definitely need the bigger pan for this one.
Hi! If making ahead of time, is it recommended to bake it, and then refrigerate it, or refrigerate it raw and then bake it in the morning? I’m trying to travel with it so I’m hoping to cook it ahead of time and then reheat it the next day but I don’t want it to come out horribly. Thanks!
It really works best to assemble, refrigerate overnight and bake in the morning.
I haven’t tested cooking and reheating the entire casserole the next day – only individual portions which works well reheated at 350 ish for 15 minutes.
I WFH and have been looking for a quick breakfast recipe and this was perfect. The fact that it is so light, made it even better. The seasoning was fine for me because the peppers added the flavor. Since I was making it just for me, I cut the recipe in half and it was still good the second day. I reheated in the microwave though.