This Vegetarian Breakfast Casserole is just the sort of recipe we need to be enjoying in PJs, at all times of day. Both—meaning the PJs and this recipe—are appropriate at any hour. It makes enough for leftovers, can be prepped well in advance (overnight if you like!), and is easily adaptable to a variety of diets and ingredients.

A pan with a vegetarian breakfast casserole sliced for a crowd with a slice of the casserole on a plate

Whether you are looking for a breakfast that vegetarians can eat, an easy recipe to enjoy all week long, or simply want a lazy-day sort of breakfast that you can eat slices of in your sweatpants at your leisure, savory egg bakes like this one are spot-on.

I consider myself a bit of a breakfast casserole connoisseur, a distinction I owe to my mother.

Whenever my mom has her three adult children—plus our spouses and my nieces—all squished back under her roof, she begins each morning with a crowd-sized breakfast. While the sides might change, a breakfast casserole is the main event.

As a collective, we prefer a savory breakfast casserole like this one over a sweet one (all the more room for a side of Puff Pastry Cinnamon Rolls). They’re almost always egg based, with lots of yummy mix-ins.

Over the years, I’ve shared a lineup of breakfast casseroles like Crockpot Egg Casserole, Everything Bagel Breakfast Casserole, and for the sweet fans, the ultimate Overnight French Toast.

I hope you’re eager for a big breakfast too. This casserole is fully loaded with roasted vegetables and although it’s vegetarian, it is plenty hearty and satisfying— fit for a breakfast feast!

Don’t let the recipe’s title fool you either; this simple vegetarian breakfast isn’t limited only to the AM hours. I love reheating it for fast, healthy lunches and dinners too.

In addition to being vegetarian, this casserole is naturally low carb and gluten free. We love ours with a shower of feta or ricotta baked on top, but it can easily be omitted if you’d like the casserole to be dairy free.

If you love a hearty, delicious breakfast that has the added benefit of being good for you, this casserole checks ALL the boxes. It’s the ideal blend of wholesome and comforting.

Low carb vegetarian breakfast casserole in a baking dish packed with vegetables

How to Make a Delicious Vegetarian Breakfast Casserole

Below, you’ll find my favorite mix of vegetables for this breakfast casserole recipe, but it is by no means the only tasty combination. Feel free to swap these out for others, depending upon what you and your family prefer.

The Ingredients

  • Sweet Potatoes. They’re deliciously surprising! You’ll love how tender and creamy they taste, and they make the casserole especially filling. If you’ve never added roasted sweet potatoes to an egg bake before, now is the time.
  • Mushrooms. Mushrooms add a touch of earthy flavor and satisfying savoriness to this casserole. Be careful not to use sliced mushrooms (buy whole ones and quarter them yourself) or they may overcook.
  • Broccoli. A green, nutrient-packed addition to this vegetarian casserole.
  • Red Bell Pepper + Onion. I love the pop of color that red bell peppers add. Once roasted, both of these veggies bring just the right amount of sweetness to the dish.
  • Eggs. The key ingredient holding casserole together. The eggs will take on all the other scrumptious flavors in the dish and add a heap of protein, making this casserole filling.
  • Milk. I typically use skim or 2%; whole milk would be richer and unquestionably delicious. Use a non-dairy milk, if you need this recipe to be dairy free.
  • Italian Seasoning. A powerhouse of seasoning that’s perfect for complementing roasted veggies.
  • Ricotta Cheese or Feta. Both are excelling pairs for the roasted veggies. This ingredient makes the casserole taste special.
  • Fresh Herbs. Basil, thyme or parsley would all work well.

The Directions

  1. Lightly coat 2 large baking sheets and a 9×13-inch casserole dish with nonstick spray. Toss the vegetables with olive oil, salt, and pepper Evenly distribute the vegetables onto the baking sheets.

    A sheet pan with roasted sweet potatoes, mushrooms, onions, red peppers, and broccoli

  2. Roast the vegetables for 20 minutes at 400 degrees F, until tender. Layer half of the roasted vegetables in the casserole dish.

    A delicious and healthy vegetarian breakfast casserole for a crowd

  3. Beat the eggs together with the milk, garlic, and Italian seasoning. Pour the mixture into the casserole dish, and add remaining vegetables on top. Dollop with small spoonfuls of the ricotta or sprinkle with feta.
  4. Bake for 35 to 40 minutes at 350 degrees F, until the top is golden. Remove, sprinkle with fresh herbs, and serve warm. ENJOY!
Low carb vegetarian egg bake topped with feta cheese

Vegetarian Breakfast Casserole Recipe Variations

  • Dairy Free. Use a non-dairy milk and omit the cheese (or use a non-dairy cheese option).
  • Gluten Free. No changes needed; this breakfast casserole is gluten free as written.
  • Low Carb. Although I adore the sweet potatoes in this recipe, they are higher in carbs than other vegetables; you can swap the sweet potatoes for a different, lower carb option. Roasted cauliflower would be delicious.
  • Potato, Egg, and Cheese. Swap the sweet potato for the same amount of diced Yukon gold potatoes. Sprinkle ½ to 1 full cup of shredded cheese such as cheddar or mozzarella over the first layer of roasted vegetables. (Or try my Healthy Breakfast Casserole with hash browns.)
  • Add Meat. Now, I truly don’t think this casserole needs meat, even if you aren’t vegetarian. That said, if you can’t resist, feel free to swap one of the sweet potatoes for 8 ounces of sautéed chicken or turkey sausage. A breakfast casserole with ham pieces would also be delicious. You can also sprinkle the top of the finished casserole with cooked and crumbled Baked Bacon.

A baking dish with an easy and healthy vegetarian breakfast recipe that's great for a crowd

Make Ahead + Storage Tips

  • To Prep Ahead. Roast the vegetables up to 2 days in advance, then add them to the recipe as directed.
  • Overnight Breakfast Casserole Prep Option. You can also fully assemble the casserole, cover it unbaked, and refrigerate it overnight. Let it come to room temperature while the oven preheats, then bake as directed.
  • To Store. Cover leftover casserole or store in an airtight storage container and place in the refrigerator for up to 3 days.
  • To Reheat. Rewarm the breakfast casserole in the oven at 350 degrees F until hot. You can also gently reheat individual slices of the casserole in the microwave until warmed through.
  • To Freeze. Store leftover casserole in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating. I like to wrap and freeze individual slices, then thaw them overnight in the refrigerator for quick meals.

What to Serve with Breakfast Casserole

  • Bread. Breakfast casserole with whole wheat toast or Easy Drop Biscuits would be a delicious, hearty meal.
  • Hash Browns. Breakfast casserole with hash browns is a combination that the entire family will love. (Might I suggest these Sweet Potato Hash Browns?)
  • Fruit. For something healthy and light, try a side of fresh fruit with this breakfast casserole.

More Vegetarian Breakfast Recipes with Eggs

A baking dish with slices of a tasty and low carb egg bake

Recommended Tools to Make This Recipe

Whether you serve it for breakfast, brunch, or brinner, I hope this vegetarian breakfast casserole becomes a well-loved meal in your home too.

If you try the recipe, please leave a comment below and let me know how it goes. I love hearing from you!

A pan with a vegetarian breakfast casserole sliced for a crowd with a slice of the casserole on a plate

Vegetarian Breakfast Casserole

5 from 18 votes
A filling and hearty vegetarian breakfast casserole with roasted vegetables and cheese. Low carb and gluten free. Prep it overnight for easy entertaining!

Prep: 15 mins
Cook: 55 mins
Total: 1 hr 10 mins

Servings: 10 servings

Ingredients
  

  • 2 medium sweet potatoes peeled and diced
  • 8 ounces whole cremini baby bella mushrooms quartered (do not use sliced mushrooms or they may overcook when roasting)
  • 1 small head broccoli cut into florets
  • 1 red bell pepper diced
  • 1 red or yellow onion cut into ½-inch dice
  • 1 teaspoon kosher salt
  • ½ teaspoon black pepper
  • 3 tablespoons extra virgin olive oil
  • 12 large eggs
  • ½ cup milk
  • 1 garlic clove minced
  • 1 ½ teaspoons Italian seasoning or dried herbs of choice
  • 4 ounces part-skim ricotta cheese
  • Chopped fresh basil thyme, or parsley (optional)

Instructions
 

  • Position racks in the upper and lower thirds your oven and preheat the oven to 400 degrees F. Lightly coat 2 large baking sheets with nonstick spray. Lightly mist a 9×13-inch casserole dish with nonstick spray and set aside.
  • Place the vegetables in a large bowl and drizzle with the olive oil. Sprinkle with salt and pepper, then toss to coat. Divide the vegetables evenly between the two sheets and spread them into a single layer. Roast the vegetables until tender, about 20 minutes, tossing the vegetables on the pan so they cook evenly and switching the pans’ positions on the upper and lower racks once halfway through. Transfer half of the roasted vegetables to the prepared casserole dish and spread into an even layer. Reduce the oven temperature to 350 degrees F.
  • Meanwhile, in a large mixing bowl, beat the eggs together with the milk, garlic, and Italian seasoning until evenly blended. Gently pour it into the casserole dish. Scatter the remaining vegetables evenly over the top, then dollop the ricotta over the top in small spoonfuls (I like to add about 20 to 24 spoonfuls; you want to each slice to have a few dollops, but have them be large enough so that you can actually taste them).
  • Bake the casserole for 35 to 40 minutes, until the casserole is golden on top and the center no longer jiggles when you shake the pan. Remove from the oven and sprinkle with fresh herbs. Serve warm.

Notes

  • TO STORE: Cover leftover casserole or store in an airtight storage container and place in the refrigerator for up to 3 days.
  • TO REHEAT: Rewarm the casserole in the oven at 350 degrees F until hot. You can also gently reheat the casserole in the microwave until warmed through.
  • TO FREEZE: Store leftover casserole in an airtight freezer-safe storage container for up to 3 months. Let thaw overnight in the refrigerator before reheating.
  • I like to wrap and freeze individual slices, then thaw them overnight in the refrigerator for quick meals.

Nutrition

Serving: 1(of 10)Calories: 188kcalCarbohydrates: 13gProtein: 11gFat: 11gSaturated Fat: 3gCholesterol: 200mgPotassium: 513mgFiber: 3gSugar: 4gVitamin A: 4774IUVitamin C: 71mgCalcium: 123mgIron: 2mg

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Erin Clarke

Hi, I'm Erin Clarke, and I'm fearlessly dedicated to making healthy food that's affordable, easy-to-make, and best of all DELISH. I'm the author and recipe developer here at wellplated.com and of The Well Plated Cookbook. I adore both sweets and veggies, and I am on a mission to save you time and dishes. WELCOME!

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73 Comments

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  1. Love this recipe! Thank you so much. I’m making this ahead of time and want to reheat. I figure 350 but how long do you think. Should I cover when reheating?5 stars

    1. I’m so happy that you enjoyed it, Diane! Thank you for sharing this kind review! You’ll want to rewarm it until it’s heated through, and you can certainly cover it if you’d like.

  2. Made this for Christmas brunch. It was a hit. I added a little sharp cheddar on the first layer and used Yukon gold potatoes. Also added more Italian seasoning. My son said it was one of the best vegetarian dishes he’s had and he’s been a vegetarian for 8 years5 stars

  3. Holy yum. So I didn’t have very many veggies on hand. But I used broccoli and red peppers. And for the cheese I used Gruyere….I will totally be making this again! More veggies next time. Haha. But yum.5 stars

    1. Hi Hannah! I’ve only tested the recipe as written, so you’d be experimenting. If you decide to try it, I’d love to hear how it goes! For an egg white only recipe, check out this Egg White Frittata recipe.

  4. Vegetarian breakfast casserole is great … tasty, satisfying … a ‘keeper’ recipe …thanks5 stars

  5. Do the sweet potatoes get cooked with the roasted veggies or just added to the base of the casserole?

    1. Hi Chris! You’ll roast the sweet potatoes with the other vegetables. I hope you enjoy the recipe!

  6. Hello! This recipe sounds so good! I’d like to prep the casserole the night before I need it and then fully bake it the day-of. Do you think the roasted veggies sitting in egg overnight will turn out well when I bake it the next day? Thanks!

    1. Hi Megan, Under my Make Ahead + Storage tips in the blog post there are details for an overnight prep option. Hope that helps!

  7. Changed out broccoli for summer Squash and ricotta for Feta. Delicious! I’m going to try the ricotta next time!5 stars

  8. I made this for a Women’s Fall Festival at our church. We had four different casseroles. This veggie casserole was a big hit! I was hoping to take some home for the next day’s breakfast but it was all gone! I will most definitely will be making this again!!!5 stars

  9. This looks delicious! My family is not a big fan of roasted broccoli. any substitution suggestions? Would zucchini or sautéed spinach work?

    1. Hi Susan! I’ve only tested this recipe as written but I’ve had other readers use squash with great success! If you decide to experiment, let me know how it goes! Hope you enjoy it!

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