Pin This savory breakfast casserole layers silky spinach with tangy feta and pillowy eggs for a dish that is hearty but light perfect to jumpstart your mornings or impress friends at brunch.
I created this recipe after hosting a big weekend brunch for my family and it quickly became one of my go-to make-ahead breakfasts because it is fuss-free and so satisfying even after reheating.
I threw this together out of necessity when my fridge was nearly empty and it turned out so well my family polished off the whole pan in one sitting. Now I always keep frozen spinach handy just for this crowd-pleaser.
Ingredients
- Olive oil: adds richness and helps the onions sauté until sweet and fragrant look for a fruity extra virgin variety
- Yellow onion: provides a savory base choose a firm onion with papery skin
- Fresh spinach or thawed frozen spinach: brings color and nutrients fresh has a delicate flavor but well drained frozen is budget friendly
- Large eggs: bind everything together with fluffy structure try to use farm fresh or cage free eggs if possible
- Whole milk: gives creaminess and body to the custard whole milk lends better texture than low fat
- Crumbled feta cheese: brings brightness and creamy saltiness use block feta for bold flavor or precrumbled feta for ease
- Shredded mozzarella cheese: optional for extra melt and pillowy texture always choose whole milk mozzarella when you can
- Salt: balances tastes without overpowering fine sea salt dissolves quickly in eggs
- Ground black pepper: adds gentle heat for a rounded flavor grind fresh if possible for best aroma
- Ground nutmeg: optional offers subtle warmth and depth choose freshly grated if available
- Day old bread such as sourdough or French: soaks up the egg mixture for structure use sturdy bakery bread for best results
- Butter or nonstick spray: for greasing ensures the casserole releases easily so slices come out clean
Instructions
- Prep the Baking Dish:
- Grease a nine by thirteen inch baking dish with butter or nonstick spray making sure to coat all the corners for easy removal
- Sauté the Aromatics:
- Heat olive oil in a skillet over medium add finely chopped onion and cook three to four minutes until translucent and fragrant this brings out the natural sweetness and builds flavor
- Cook the Spinach:
- Add chopped fresh spinach or thawed drained frozen spinach to the pan cook until wilted if fresh or warmed through if frozen then take off the heat and let cool briefly so it does not scramble the eggs
- Mix the Custard:
- In a large mixing bowl whisk together eggs milk salt black pepper and nutmeg if using keep whisking until no streaks of yolk remain for the fluffiest base
- Combine the Mix-ins:
- Add sautéed spinach and onion cubed bread crumbled feta and mozzarella to the egg mixture fold together gently until all pieces of bread are soaked
- Assemble the Casserole:
- Pour the egg and veggie mixture into your prepared baking dish then smooth the top with a spatula for even baking
- Bake Until Set:
- Place in the preheated oven and bake thirty five to forty minutes or until the center is just set and the top is lightly golden check with a knife if unsure
- Rest and Serve:
- Let the casserole rest for five minutes to firm up before cutting into squares and serving enjoy warm
Pin My kids always argue over the crisp corners where the bread gets extra golden and the feta melts into little creamy pockets. Feta is my favorite part because it adds the perfect tang and wakes up the sleepy flavors early in the morning.
I will never forget the time my mother tasted this casserole for the first time and said it reminded her of her favorite Greek omelet so now it is a staple whenever she visits.
Storage Tips
Store leftovers tightly covered in the fridge for up to four days and reheat gently in the oven or microwave. I like to cut the casserole into single servings before storing to make grab and go breakfasts super easy. If you wish to freeze individual slices wrap them well and thaw overnight in the fridge or pop straight into the oven to warm.
Ingredient Substitutions
Feel free to use gluten free bread if needed or swap the feta for goat cheese or shredded cheddar. For a dairy free version use unsweetened almond milk and omit the mozzarella and feta replacing with your favorite tangy vegan cheese. You can also add fresh herbs like dill or chives or sneak in some chopped bell peppers or mushrooms for a veggie boost.
Serving Suggestions
Serve slices with a simple green salad topped with vinaigrette or fresh fruit for a complete meal. For brunch add a side of crispy breakfast potatoes and a pitcher of fresh juice. For quick weekday breakfasts I love wrapping a piece in foil and taking it with me when I am running late.
Cultural or Historical Context
This casserole takes inspiration from classic strata and Greek spanakopita adding bread cubes for substance like American casseroles and using savory feta and spinach for a Mediterranean twist. It is a practical dish that brings worlds together making everyday ingredients feel a little bit special.
Seasonal Adaptations
Swap the spinach for baby kale or Swiss chard in spring or summer. Mix in roasted butternut or mushrooms in the fall or winter. Top with sliced tomatoes or fresh herbs at serving for brightness.
Success Stories
I have had letters and texts from friends who have made this casserole for book clubs holiday mornings and even weddings because it feeds a crowd and always impresses. It is one of those recipes that you will get asked for over and over just like I did after my neighborhood brunch potluck.
Freezer Meal Conversion
Assemble the casserole in the baking dish cover tightly and freeze before baking. Thaw in the refrigerator overnight then bake as directed or add an extra five to ten minutes if baking straight from cold. Individual baked portions can also be frozen and reheated straight from the freezer.
Pin This recipe is endlessly flexible and forgiving so do not be afraid to make it your own for any occasion.
Recipe Q&A
- → Can I use frozen spinach instead of fresh?
Yes, thaw and drain frozen spinach well before adding. It works just as well as fresh.
- → How do I make this gluten-free?
Simply substitute gluten-free bread for the day-old bread. Check labels for allergens.
- → Can the dish be assembled ahead of time?
Absolutely. Assemble, cover, and refrigerate overnight. Bake fresh in the morning.
- → What vegetables can I add for extra flavor?
Try sun-dried tomatoes or roasted red peppers for extra color and taste.
- → How can I serve this for brunch?
Pair each slice with a crisp green salad or fresh fruit for a satisfying brunch plate.