This Make Ahead Breakfast Casserole is loaded with veggies, cheese, and eggs. It’s very easy to make and is a perfect hearty breakfast for Christmas morning!
I love making casseroles like my Cauliflower Casserole Recipe and Zucchini Casserole Recipe because they’re so easy to make. So it wasn’t long before I tried to make a casserole for breakfast instead!
Today, I share this make-ahead breakfast casserole recipe that you will love because it’s so D.E.L.I.C.I.O.U.S., and at the same time, it’s very versatile! You can use any fresh veggies you have in your fridge.
I used what I had available, such as red onions, broccoli, mushrooms, cherry tomatoes, and spinach.
But if you don’t have one of these ingredients to make this overnight breakfast casserole, you can still make it. You can add anything you please, such as red bell peppers, sweet potatoes, cauliflower, potatoes, or shredded potato hash browns and the list goes on and on.
Also, choose your favorite cheese. I added a mixture of cheddar cheese and mozzarella, but this overnight breakfast casserole also goes really well with Swiss or even goat cheese. It’s totally up to you! If you avoid dairy, simply skip this ingredient. No problem at all.
This make-ahead egg casserole breakfast is full of goodies like fresh vegetables and protein, which makes it hearty and keeps you satisfied for hours. It always feels good to get those veggies in first thing in the morning, don’t you think?
I really think it would be an amazing recipe for Christmas morning breakfast for two reasons. First, it’s the perfect way to use leftovers from your holiday meals (I always have extra veggies because of my go-to Ground Beef Veggie Skillet Recipe and Roasted Parmesan Green Beans for dinner). Second, you’ll have free time to open your gifts, give presents, and enjoy the special Christmas morning since you can make it ahead and just bake it in the morning.
Believe me, this Make-Ahead Vegetarian Breakfast Casserole makes a great overnight casserole. Prepare everything the night before, such as chopping and sautéing the veggies. Then, pour the egg mixture over top, add the cheese, and then cover with foil. Refrigerate it overnight, and then bake it in the morning.
This is a make-ahead vegetarian breakfast casserole but if you are not doing a vegetarian dish you can add ham and even bacon. It’s very good!
It’s very good, gluten-free, and low-carb! This breakfast will absolutely make your Christmas morning merry and very special. This is also a great recipe for Easter brunch!
Want another easy breakfast recipe? Try this Chia Seed Pudding Recipe!
- Extra virgin olive oil — or you can use any oil you prefer or even butter.
- Red onions — or whatever onion you have on hand. Skip red onions if you’re following a keto diet.
- Broccoli — chopped the broccoli into bite-sized pieces.
- Mushrooms — feel free to buy pre-sliced mushrooms or slice your own.
- Cherry tomatoes — you can also use grape tomatoes as well.
- Fresh spinach — always wash your spinach before using.
- Eggs — I use large eggs that are free-range eggs. You are more than welcome to use whatever eggs you have, including farm-fresh eggs.
- Almond milk or non-dairy milk — I prefer dairy-free milk. But use any milk of choice.
- Seasoning — I use garlic powder, mustard powder, salt, and pepper.
- Cheese — I use a mix of cheddar and mozzarella cheese.
- Sal and black pepper
- Parsley, green onions, or basil— for garnishing (optional). You can use any fresh or dried herbs you have on hand. Sprinkle any herb on top to add more flavor.
Prepare the equipment
- Preheat oven to 325°F.
- Spray a 9×9-inch casserole dish or baking pan with a good coating of cooking spray, and set aside.
Cook the vegetables
- In a large skillet over medium heat, add the olive oil and then add the onions, and cook until they are soft.
- Then, add the rest of the veggies, stir well, and sauté until they are tender.
Transfer everything to the baking dish and bake
- Add the sauteed veggie mixture to the baking dish.
- Whisk together the eggs, almond milk, garlic powder, mustard powder, salt, and pepper in a bowl.
- Pour the egg mixture over the veggie mixture in the baking dish. Top with the cheese and cover with foil. Bake for 40 minutes.
- Remove the foil, and cook an additional 10 minutes, or until the egg mixture is cooked through.
- Let it cool for 5 minutes before serving.
Recipe tips and notes
- Make sure to let this egg casserole rest before you slice so it has a chance to set.
- Feel free to add more or swap the vegetables to this overnight breakfast casserole. Other veggies you can try are cauliflower, carrots, kale, and bell peppers.
- Other cheeses you can use are parmesan, Gruyere, pepper jack, feta, goat cheese, or swiss cheese.
- Leftovers: cover leftover casserole or transfer to an airtight storage container and place in the refrigerator for up to 3 days. Reheat in the oven or microwave.
- Freezer: Transfer leftover veggie breakfast casserole to an airtight freezer-safe container. You can freeze it for up to 3 months.
- Reheat: When ready to eat, let the casserole thaw overnight in the refrigerator before reheating.
Watch the Web Story HERE.
More Casserole Recipes to try:
- Spaghetti Squash Casserole Recipe
- Cauliflower Casserole Recipe
- Brussels Sprouts Casserole Recipe
- Sausage and Hash-Brown Breakfast Casserole
- Broccoli and Cauliflower Casserole Recipe
Make Ahead Breakfast Casserole
Video
Ingredients
- 2 tablespoons extra virgin olive oil
- 1 cup red onions chopped (skip red onions if you're folling a keto diet)
- 2 cups broccoli chopped
- 3 cups mushrooms sliced or chopped
- ½ cup cherry tomatoes
- 2 cups fresh spinach
- 6 eggs
- ½ cup almond milk
- ½ teaspoon garlic powder
- ¼ teaspoon mustard powder optional
- Salt and pepper to taste
- 1 cup cheddar and mozzarella cheese mix
- Parsley for garnishing (optional)
Instructions
- Preheat oven to 325°F. Spray a 9×9-inch casserole dish with a good coating of cooking spray, and set aside.
- In a medium skillet, add the olive oil over medium heat. Add the onions, and cook until they are soft.
- Then, add the rest of the veggies, and sauté until they are tender. Add this veggie mixture to the baking dish. Set aside.
- While the veggies are cooking, whisk together the eggs, almond milk, garlic powder, mustard powder, salt, and pepper in a bowl.
- Pour the egg mixture over the veggie mixture in the baking dish.
- Next, add the cheese.
- Cover with foil, and bake 40 minutes. Remove the foil, and cook an additional 10 minutes, or until the egg mixture is cooked through.
- Let it cool for 5 minutes before serving.
Notes
- Allow the casserole to set before cutting, so the casserole holds up when you serve it.
- Feel free to add more vegetables such as cauliflower, carrots, kale, and bell peppers.
- Parmesan, Gruyere, pepper jack, feta, and goat cheese are a great alternative to cheddar and mozzarella.
- To store: Leftovers can be kept in a container in the fridge for up to 5 days.
- To reheat: Reheat the casserole in the microwave or in the oven.
- To freeze: Wrap up the casserole tightly and freeze for up to 3 months. You can reheat it once fully thawed.
Nutrition
Nutrition information is automatically calculated, so should only be used as an approximation.
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I just made it this morning- so easy and delicious!! I nuked frozen chopped spinach, drained it and added it to my cooked onions and mushrooms. I was out of almond or regular milk so I added 1/2 cup cottage cheese and 1/4 cup liquid egg whites. (Dairy is fine for me). I wasn’t sure about the mustard powder so I left it out and added some poultry seasoning. Next time I will try mustard- it might be great.
I am going to whip this up on Sunday nights so I’ll have a quick breakfast during the week. So yummy! Thank you
Awesome. Happy to hear that 😉
This sounds delicious. I plan on making this for my daughter (she just had her first child) Is it better to cook this before freezing?
Sorry Tomiko, but I’m not sure if this recipes freezes well. After you cook, it’s good in the fridge for 4 days.
Can this be made ahead and frozen uncooked?
I believe so but I’ve never frozen this recipe uncooked before. I can’t really confirm 100% that it will work.
Did you dice all the vegetables? How did you cut the broccoli? Do i have to dice the onion and mushroom?
Also how did you measure 0.75 egg? Did you only use the egg yolk or egg white?
I used 6 whole eggs.
Yes you have to dice/chop all the veggies.
Egg-cellent recipe and delicious!I used about 7 different veggies, including tomato and zucchini. I used 8 eggs and topped with sharp cheddar, feta and grated Parmesan cheeses. Due to the extra veggies I cooked it an extra 10 minutes. The result was so amazing! Great for breakfast or any meal with a dab of salsa. I’m subscribing for more of your great recipes.
Thank you for helping me cook healthy!
Thank you for your comment and for making this recipe. It’s really good. Also, thanks for subscribing to my newsletter and for all the support. I appreciate it a lot 😉
Assembled last pm, stuck in fridge, and just woke up and popped in the oven. Looking forward to eating a delicious, quick n easy, healthy thought-out breakfast for Christmas morning! Thanks so much for posting!
you’re very welcome. Hope you liked it!
This recipe is so good. I am trying to squeeze more fruits and veg into my diet and this is perfect to make ahead (I made a couple of casseroles at the same time and froze the individual pieces then vacuum sealed them). So perfect to heat up quickly in the morning! I love that you can make it anyway you want– I made it with mushrooms, leeks, asparagus, spinach, and sun dried tomato with gruyere cheese on top. So yummy!
Mmm.. gruyere cheese works very well with this recipe. Happy you liked it.
This recipe is a weekly mainstay for me. I change up the veggies and the cheese. It is so yummy. My family loves it and looks forward to eating it (never any leftovers), even my two-year old twin grandchildren love it! Thanks for all the great recipes.
Your comment made my day. Thank you so much for stopping by and for leaving your feedback. I appreciate it!
How to make without oven
You can cook it in a skillet on low temperature and close the skillet with a lid. Be careful to not burn the frittata!
Can you use crescent rolls then add egg mixture??
I believe you can, but I’m not completely sure just because I’ve never made this recipe with crescent rolls. But let me know if thy try it. I would like to know how it turned out. Thanks