Butternut Squash and Spinach Breakfast Casserole

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This easy Butternut Squash and Spinach Egg Casserole is filling, packed with veggies, and delicious. Serve it for breakfast, lunch, or dinner!


I'm a big fan of breakfast. I mean, what's not to like? It's the first meal of the day, you can have any combination of foods — cereal and dairy, protein and grains, fruit and dairy, grains and nuts...the list goes on. However, I've also been on a savory kick. I've been wanting to wake up to the smell of something delicious — something that combines almost all my favorite breakfast foods into one and something that is also good for me. That's where this breakfast casserole comes in.

Since butternut squash is in season right now, it was my natural choice for a more substantial veggie to put into the casserole. And spinach and feta just seem to go with the squash naturally. And then, when you add the eggs and other ingredients to make a casserole, well, that's just the stuff right there.

The combination of butternut squash, spinach, and feta ranks up there as one of my favorites, especially when it's all baked together in a tasty breakfast dish like this. Lately I have been enjoying making a big egg dish on Sundays that I can just use as a grab-and-go meal during the week as part of my meal planning. It makes breakfast easy and mindless, which is exactly what I need until I reach coffee number three. Plus, the protein from the eggs keeps me full all morning.

Ideas for Customizing a Butternut Squash and Spinach Breakfast Casserole

The great thing about this meal is that there are sooooo many ways to make it your own!

  • Sub out the butternut squash for any other squash or veggies that you like. Asparagus, zucchini, yellow squash, or broccoli will work well here.
  • You can use kale instead of spinach — or both!
  • You can use some egg whites or Egg Beaters instead of whole eggs if you like.
  • Add black olives, capers, artichoke hearts, or roasted red peppers to give the dish more of a Mediterranean taste.
  • Add biscuit dough to the bottom of the pan first, if you want a little bit of bread with your casserole (you might have to adjust cooking time).
  • Better yet, add a slice of this casserole between two pieces of sprouted grain bread for an even more nutritious breakfast.

Side view of butternut squash and spinach egg casserole with blurred background.

What Makes this Butternut Squash and Spinach Breakfast Casserole Healthy?

It's always good to start the day off on a healthy note I think. And this dish is no exception. It's chock full of healthy ingredients that all do good things for your body.

  • Olive oil is a great base oil that's good for cooking with and for adding to salad dressings, marinades, and a whole lot of other foods. It provides the good kind of heart-healthy fat and antioxidants.
  • Butternut squash is full of fiber, vitamin A, and potassium. It's also low calorie and has protein, iron, and vitamin C as well.
  • Red onions contain flavonoids and phytochemicals which help to ward off disease, cancer, and infection.
  • Spices like salt, garlic powder, oregano, and pepper not only make your food flavors soar, but they also deliver nutrients like vitamins, minerals, and anti-inflammatory properties that keep your body healthy.
  • Spinach is chock full of iron; vitamins A, C, and K1; protein; and fiber and it's low-carb and low-calorie.
  • Eggs provide healthy cholesterol, protein, antioxidants, and are very filling, despite being a low-calorie food.
  • Reduced fat feta cheese is a salty cheese that has less fat than other cheeses. It also contains zinc, folate, selenium, vitamin B6, and zinc.

How Do You Prepare and Cook Butternut Squash?

Butternut squash is tough to cut so you'll need a sharp knife. First, I take off the top and bottom of the squash to make a flat surface. then, I like to use a vegetable peeler to remove the skin. I then cut it in half, remove the seeds, then go about dicing it up as you would any other vegetable. It will just take a little longer — but it's worth the effort.

For cooking it, you can saute it as I did here for this recipe, or bake it, like I did with these Butternut Squash Fries. Or, you can cook it and blend it up into soup.

Butternut Squash and Spinach Egg Casserole in a pan with a cutting board underneath.

How to use this Egg Casserole in Meal Planning

I mentioned that this casserole is great for meal planning. You might be wondering what that is and how I incorporate this dish into my meals for the week. Meal planning is when you choose recipes that you want to make for the week ahead of time. So, you'd go through your cookbooks, social media, or magazines and collect recipes that you think you'd like to eat. Then, plan out when you want to eat them (I like to make a google doc), how frequently, and what ingredients you'll need. Then you create a list for the grocery, shop, and bring all your goodies home.

You can either plan what you want to make for the week ahead on a daily basis, or plan to make some meals in bigger batches and eat them throughout the week, like I do with this casserole. I'll make it on Sunday, and have enough servings to have it every breakfast again for the rest of the week. It's so much easier than you think and so worth the work in advance.

The Recipe
Butternut Squash and Spinach Breakfast Casserole in a cast iron skillet with a napkin.

Butternut Squash and Spinach Breakfast Casserole

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  • 1 tbsp olive oil
  • 3 cups butternut squash, peeled and diced
  • 1/2 red onion, diced
  • 3/4 tsp salt
  • 3/4 tsp garlic powder
  • 3/4 tsp oregano
  • 3/4 tsp pepper
  • 6 cups spinach, chopped
  • 12 eggs
  • 1 cup reduced fat feta cheese

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Preheat the oven to 400 degrees.


Add the olive oil to the pan. Once hot, add the butternut squash and red onion. Cook for 8-10 minutes until squash and onion are tender, adding 1-2 tablespoons of water if burning. Add the salt, garlic powder, oregano, and pepper. Stir together. Add the spinach and cook until it wilts, 1-2 minutes.


Whisk together the eggs and feta. Add the butternut squash mixture to a baking dish sprayed with cooking spray. Pour the eggs over top. Bake for 20-25 minutes until eggs set and are cooked through.

Nutritional Facts
Serving Size: 1 piece
Amount Per Serving
Calories 251
Calories from Fat 132
% Daily Value *
Total Fat 15g
Saturated Fat 5g
Monounsaturated Fat 0g
Polyunsaturated Fat 0g
Cholesterol 381mg
Sodium 767mg
Total Carbohydrate 12g
Dietary Fiber 2g
Sugars 2g
Protein 19g

* Percent Daily Values are based on a 2,000 calorie diet. Your daily values may be higher or lower depending on your calorie needs.

The Nutritional Values provided are estimates only and may vary based on the preparation method.

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About the author Meet Kristen McCaffrey
Hi, I’m the cookbook author, recipe developer, and food enthusiast behind Slender Kitchen. I am obsessed with making healthy food that is easy to prepare and absolutely delicious. Meal planning is my secret weapon and I hope I can make meal time easier for you with our tried and tested recipes and foolproof meal plans. Learn More
On Butternut Squash and Spinach Breakfast Casserole
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October 25, 2023 - 17:34
Could you use frozen butternut squash in this recipe and if so would it have to be thawed?
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October 26, 2023 - 08:57
Frozen butternut squash would work great. You can either cook it in the pan from frozen or defrost it, both will work. If you cook it from frozen., just keep an eye on it so it doesn't burn on the outside.
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