Breakfast Casserole with Spinach Feta

Featured in: All-American Breakfasts

This wholesome breakfast dish combines fresh spinach, creamy feta, and fluffy eggs for a savory start to your day. Sweet red bell pepper and onion add vibrant flavor, while mozzarella lends a mild, cheesy finish. Make it ahead for hassle-free mornings or bake fresh for a warm family brunch. Versatile and easy, it’s a satisfying vegetarian option the whole table will enjoy!

Updated on Sun, 05 Oct 2025 11:49:41 GMT
Breakfast Casserole with Spinach and Feta baked golden with creamy cheese and colorful veggies. Pin
Breakfast Casserole with Spinach and Feta baked golden with creamy cheese and colorful veggies. | panpatriot.com

This savory breakfast casserole brings together fluffy eggs, creamy feta, sweet bell pepper, and plenty of spinach for a cozy meal. It is my favorite trick for feeding a crowd on busy mornings or for making sure weekday breakfasts are set with little effort.

When a holiday morning calls for something special yet simple I turn to this casserole. My family loves waking up to the smell of it baking and I appreciate having breakfast sorted ahead of time.

Ingredients

  • Fresh spinach: Provides tender greens and color Look for leaves that are dark green without yellowing or slimy spots
  • Yellow onion: Sweeter and milder than other onions Adds great base flavor Choose a firm onion with no soft spots
  • Red bell pepper: Adds sweetness and color to the dish Pick one that is bright and glossy with no wrinkling
  • Large eggs: Make the protein rich base of the casserole Freshest eggs have tight whites and vibrant yolks
  • Milk: Creates custardy texture Whole or two percent both work well
  • Crumbled feta cheese: Adds creamy tang and saltiness Briny feta from a block is best for flavor and texture
  • Shredded mozzarella cheese: Makes this extra melty and satisfying Choose full fat mozzarella for best melt
  • Olive oil: Used for sautéing vegetables Pick extra virgin with a fruity or peppery aroma
  • Salt: Enhances all the savory notes Opt for sea salt or kosher salt
  • Freshly ground black pepper: Gives gentle heat Fresh grind for more flavor
  • Dried oregano: Offers an herby undertone Greek or Mediterranean origin is ideal
  • Optional: Sun dried tomatoes: Bring little bursts of umami and tang Oil packed tomatoes are softer and easier to chop

Instructions

Preheat the Oven:
Set your oven to 375 degrees Fahrenheit which allows enough time for even baking without browning the eggs too much. Lightly grease a 9 x 13 inch baking dish with olive oil or a swirl of nonstick spray ensuring every corner is covered so the casserole releases easily later.
Sauté the Vegetables:
In a roomy skillet warm olive oil over medium heat until shimmering. Add diced onion and chopped red bell pepper. Let them cook gently for three to four minutes stirring just enough to keep them from sticking. You want the vegetables softened and fragrant but not overly browned which helps build subtle layers of flavor.
Wilt the Spinach:
Add chopped spinach in batches if needed so it fits in the pan. Toss gently until it reduces in volume and loses its raw texture usually in about two minutes. Turn off the heat and let these vegetables cool slightly so they do not scramble your eggs later.
Whisk the Egg Mixture:
In your largest mixing bowl crack in all eight eggs. Add milk salt black pepper and oregano. Whisk vigorously until the yolks are completely broken up and everything looks pale yellow with tiny bubbles showing it is well aerated. This gives your casserole a light soufflé texture.
Combine Everything:
Fold sauteed vegetables into the egg mixture making sure they distribute evenly. Sprinkle in the crumbled feta mozzarella and optional sun dried tomatoes stirring gently until all components are coated in egg. Small curds of feta throughout make every bite flavorful.
Bake the Casserole:
Pour the filling into your prepared dish smoothing the top so it is level. Place in the center of the oven and bake for thirty five to forty minutes. The center should look set when gently jiggled and the top will develop a blush golden color. If using a glass dish check for doneness at thirty five minutes.
Rest and Serve:
Allow your casserole to cool for at least five minutes before slicing. This resting period helps each square firm up making neat slices and letting the flavors meld. Serve while warm ideally with something crisp and green on the side.
Freshly sliced Breakfast Casserole with Spinach and Feta served hot for a cozy morning meal. Pin
Freshly sliced Breakfast Casserole with Spinach and Feta served hot for a cozy morning meal. | panpatriot.com

My favorite part is always the bites where creamy feta and juicy bell pepper meet. I remember my son begging for seconds the first time we served this on Christmas morning which instantly made it a family tradition.

Storage Tips

Slice your casserole and store pieces in airtight containers Once fully cooled they hold up beautifully in the fridge for up to four days I like reheating individual portions in the microwave or oven for best results For longer storage freeze slices wrapped in foil or parchment then tuck into freezer bags Defrost overnight in the fridge and warm in the oven till piping hot

Ingredient Substitutions

Swap the spinach for kale Swiss chard or any sautéing leafy green If you want a lactose free dish use plant based milk and skip the cheese or use vegan alternatives Other cheeses like goat cheese or sharp cheddar give a different twist both work well

Serving Suggestions

This casserole is lovely with a side salad of arugula or baby greens and a wedge of toast such as rustic sourdough On weekends I will make a platter with sliced fruit or citrus for a brunch spread You can also tuck slices of leftover casserole into a breakfast sandwich with tomato and avocado

Cultural and Historical Context

Egg based breakfast bakes are a mainstay in American home kitchens drawing some inspiration from European dishes like Greek spanakopita The combination of spinach feta and eggs celebrates simple produce and fresh cheese transforming humble ingredients into something worthy of a family gathering

Seasonal Adaptations

Add roasted butternut squash in the fall for a little sweetness Fresh basil or parsley in spring brightens up the flavor Try roasted cherry tomatoes in summer when they are at their peak

Success Stories

My friend made this with her young daughter who got to sprinkle the cheese and pour in the eggs For them it became their go to recipe for Saturday mornings When I am hosting overnight guests I count on this casserole to impress them without much effort

Freezer Meal Conversion

Make this casserole fully through the baking step Let it cool completely wrap tightly and freeze for up to two months When ready to serve thaw overnight in the refrigerator and warm in a low oven before slicing The texture stays remarkably fluffy

Cheesy Breakfast Casserole with Spinach and Feta, ready on a brunch table with a salad. Pin
Cheesy Breakfast Casserole with Spinach and Feta, ready on a brunch table with a salad. | panpatriot.com

Serve warm with crisp salad greens and a cup of coffee for a breakfast that feels like a treat every time.

Recipe Questions

Can I make this casserole ahead of time?

Yes, you can assemble the casserole the night before. Refrigerate it overnight and bake in the morning when ready to serve.

What can I substitute for spinach?

Kale or Swiss chard work well as substitutes for spinach and add a similar leafy texture and flavor.

How do I store leftovers?

Allow the dish to cool, then store leftovers in an airtight container in the refrigerator for up to three days.

Can I add other vegetables?

Absolutely, try adding mushrooms, zucchini, or sun-dried tomatoes for extra flavor and nutrients.

Is this breakfast suitable for vegetarians?

Yes, the dish uses eggs and cheese but contains no meat or fish, making it vegetarian-friendly.

What sides go well with this?

Pair with a simple green salad, roasted potatoes, or toasted sourdough for a complete meal.

Breakfast Casserole with Spinach Feta

Fluffy casserole with spinach, feta, and eggs—ideal for a make-ahead breakfast or quick brunch.

Prep duration
15 min
Cooking duration
40 min
Total duration
55 min


Difficulty Easy

Origin American

Yield 6 Servings

Dietary requirements Vegetarian, Gluten-free

Ingredients

Vegetables

01 5 ounces fresh spinach, roughly chopped
02 1 medium yellow onion, finely diced
03 1 red bell pepper, diced

Dairy & Eggs

01 8 large eggs
02 1 cup whole or 2% milk
03 1 cup crumbled feta cheese
04 1/2 cup shredded mozzarella cheese

Pantry & Seasonings

01 2 tablespoons olive oil
02 1/2 teaspoon salt
03 1/4 teaspoon freshly ground black pepper
04 1/4 teaspoon dried oregano

Optional

01 1/4 cup sun-dried tomatoes, chopped

Directions

Step 01

Prepare Baking Dish: Preheat oven to 375°F. Lightly grease a 9x13-inch baking dish with olive oil or nonstick spray.

Step 02

Sauté Vegetables: Heat olive oil in a large skillet over medium heat. Add diced onion and red bell pepper; cook for 3 to 4 minutes until softened.

Step 03

Wilt Spinach: Add chopped spinach to the skillet. Cook for approximately 2 minutes until just wilted. Remove from heat and allow vegetables to cool slightly.

Step 04

Prepare Egg Mixture: In a large mixing bowl, whisk eggs, milk, salt, black pepper, and oregano until thoroughly blended.

Step 05

Combine Casserole Filling: Gently fold sautéed vegetables, crumbled feta, shredded mozzarella, and sun-dried tomatoes (if using) into the egg mixture.

Step 06

Fill and Bake: Pour the prepared mixture evenly into the greased baking dish. Bake for 35 to 40 minutes, until the center is set and the top is lightly golden.

Step 07

Cool and Serve: Allow casserole to cool for 5 minutes before slicing. Serve warm, garnished with fresh herbs if desired.

Necessary tools

  • Large skillet
  • Mixing bowl
  • Whisk
  • 9x13-inch baking dish
  • Knife
  • Cutting board

Allergy information

Review each ingredient for potential allergens and consult with healthcare providers if you're uncertain.
  • Contains eggs and dairy. Check cheese labels for traces of gluten or nuts.

Nutrition facts (per portion)

These values are estimates only and shouldn't replace professional medical guidance.
  • Calories: 225
  • Fat: 14 g
  • Carbohydrates: 7 g
  • Protein: 15 g