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This healthy breakfast casserole has a whopping 3 pounds of veggies hidden inside, but it tastes like a classic egg dish that you’d enjoy for a holiday meal.
The secret ingredient? Spaghetti squash.
This winter squash has a neutral enough flavor that it blends right in with the eggs and cheese. It tastes like Quiche Lorraine, and the spaghetti squash adds a hash brown-like texture to the dish. (Only with a lot less starch.)
Once you taste this healthier breakfast casserole, you may want to make it part of your regular meal prep routine while squash is in season!
⭐⭐⭐⭐⭐ Featured Review
“This has become our family’s go-to egg bake!” – Breanna
Ingredients You’ll Need
- Spaghetti Squash. You’ll need a medium-sized spaghetti squash for this recipe, which is 3 to 3.5 pounds when you’re weighing a raw squash. I recommend cooking this ahead of time for for an easier morning.
- Eggs. I recommend using 8 large eggs as a minimum amount, but you could use 10 eggs if you want a thicker casserole.
- Shredded Cheese. I like to make this with Gruyere cheese when possible, because that makes it taste like classic Quiche Lorraine. But if you’re not a fan of Swiss cheese, try making this with sharp white cheddar, instead. It’s amazing either way!
- Bacon. My mom’s breakfast casserole was always made with bacon, so that’s what we’re using here, too. I usually bake a whole 12 ounce package the day before, serve a few slices that day, and then use the leftover bacon in this casserole.
- Onion. Sauteed yellow onion adds another layer of flavor that you’d expect to find in a breakfast casserole.
- Salt and Pepper. These help boost the flavor in the egg mixture, so it’s evenly distributed throughout the casserole.
How to Make Breakfast Casserole with spaghetti squash
Step 1:
I recommend cooking the spaghetti squash and bacon ahead of time. Preheat your oven to 400ºF, and since the squash takes the longest to cook, start with that.
Cut the squash in half cross-wise, meaning you’ll cut through only the center of the squash where it’s the most hollow. (This is the easiest way to cut a spaghetti squash, in my opinion.)
Use a spoon to remove the seeds, then place the halves cut-side-down on a rimmed baking sheet lined with parchment paper. Bake at 400ºF until the squash is tender, about 45 to 60 minutes.
Now that the squash is cooking, arrange the bacon in a single layer on another rimmed sheet pan. Avoid any overlap for the crispiest results. Cook the bacon at 400ºF for 20 to 25 minutes, or until it looks crispy. You can do this on a second shelf in the oven while the spaghetti squash is cooking, to maximize your time.
Step 2:
To cook the onion, add a drizzle of olive oil to a skillet over medium-high heat. Let the pan preheat for 1 to 2 minutes, then add the onion and stir often. Cook until the onion is soft and translucent, about 6 to 8 minutes. Then set it aside to cool.
Next, use a fork to scrape the cooked spaghetti squash strands into a large mixing bowl.(it should be cool enough to handle; especially if you prepped it the night before.) Then add about 4 strips of crispy, chopped bacon. To make this dish vegetarian, you can omit the bacon.
Transfer the cooked onion and half of the shredded cheese to the bowl, too.
Step 3:
Crack the eggs into a separate bowl, just to make sure you can scoop any broken egg shells out easily. Mix in the salt and pepper, and whisk well with a fork.
Pour the egg mixture into the large bowl and stir well. Then pour the mixture into a greased baking dish. (I use a 9-inch by 13-inch baking dish.)
Sprinkle the remaining cheese and any reserved bacon pieces over the top, then bake at 400ºF for 40 to 45 minutes, or until the top looks golden and the center of the breakfast casserole has puffed up in the center.
Serving Tips
Remove the pan from the oven and let it cool for 15 to 20 minutes, before slicing and serving. I like to sprinkle a few chopped chives over the top, for a pop of color.
Leftovers can be stored in an airtight container in the fridge for up to 5 days. It’s such an easy breakfast to reheat throughout the week!
Healthy Breakfast Casserole (with Spaghetti Squash!)
Ingredients
- 1 (3-pound) spaghetti squash
- 6-8 ounces thick-cut bacon
- 1 tablespoon olive oil
- 1 medium yellow onion , chopped
- 8 large eggs
- 5 ounces Gruyere or extra-sharp cheddar cheese , shredded and divided
- 1 ½ teaspoons fine sea salt
- ½ teaspoon black pepper
Instructions
- Preheat your oven to 400ºF and gather two rimmed baking sheets. Cut the spaghetti squash in half crosswise (so you only cut through the hollow middle– easier!) and scoop out the seeds with a spoon. Place the squash cut-side-down on the pan, and bake until tender, about 45 to 60 minutes.
- To cook the bacon, arrange the strips in a single layer, without overlap, on the other lined baking sheet. (Make sure it has a rim, to catch the grease as it cooks.) Place it in the same oven as the squash and let it cook until crisp, about 25 to 30 minutes, depending on the thickness. It will crisp up even more as it cools. Note: I usually cook a whole 12-ounce package of bacon, but only 6 to 8 ounces is needed for this recipe. Feel free to snack on the rest!
- Once everything is in the oven, add the olive oil to a large skillet over medium heat and sauté the onion until it is soft and translucent, about 5 to 8 minutes. Set it aside to cool while everything else finishes cooking.
- Let the spaghetti squash and bacon cool, until they are comfortable enough to handle. (You don't want to mix the eggs into piping hot squash, or they will scramble as you stir. This is why I recommend cooking the squash and bacon the night before you want to assemble this casserole, so you don't have as much prep time in a single day.) Once you can handle the squash, use a fork to scrape the spaghetti squash strands into a large mixing bowl. Chop 6 to 8 pieces of crispy bacon in to pieces, and sprinkle them into the bowl, too. (Reserve a few bacon pieces to sprinkle on top, if you like.)
- Crack the eggs into a separate bowl (just in case you need to fish out broken egg shells later) and season with the salt and pepper. Whisk well with a fork, then pour it into the mixing bowl, along with the onions, and half of the grated cheese. Stir well.
- Grease a 9" by 13" baking dish with spray oil, then pour the mixture into the pan. Sprinkle the remaining cheese over the top, along with any reserved bacon pieces. Bake until the top is golden and has puffed up, about 40 to 45 minutes at 400ºF.
- When the breakfast casserole is done cooking, remove it from the oven and let it cool for 10 to 15 minutes. Slice it into 12 squares and serve warm, with a few freshly chopped chives on top, if desired. Leftovers can be stored in an airtight container in the fridge for up to 5 days.
Notes
- Nutrition information is for 1 of 12 slices, assuming you use 6 ounces of bacon. This information is automatically calculated, and is just an estimate, not a guarantee.
- This recipe was updated in December 2022, to increase the salt from 1 teaspoon to 1 1/2 teaspoons. If you prefer using less salt, feel free to use the original 1 teaspoon, but I think the flavor is better with the extra 1/2 teaspoon addition.
- For make-ahead tips, be sure to read the full post above!
Nutrition
More Recipes to Try
If you try this breakfast casserole recipe, please leave a comment and star rating below letting me know how you like it!
This has become our family’s go-to egg bake!
Delicious
This recipe is delicious. I’ve shared it with lots of friends. Had the left overs with salsa and sour cream. Amazing!!!