This Spinach, Tomato & Feta Breakfast Casserole is one of those go-to recipes that’s easy to whip up, full of fresh flavors, and super satisfying. It’s cheesy, savory, and packed with veggies—and you can prep it the night before for a no-stress morning. Perfect for a slow weekend brunch or even meal prep for the week.
You’ll love the fluffy eggs, juicy tomatoes, tangy feta, and a light layer of golden melted cheese on top. Every bite is loaded with flavor.
Why I Love This Recipe
This one reminds me of lazy Sunday mornings with the windows open and coffee brewing. I started making it after a trip to Greece where I fell in love with feta and spinach in everything. Since then, this has become a family favorite. It’s hearty but not heavy, easy to put together, and tastes even better the next day.
- Easy to prep ahead
- Full of protein and veggies
- No fancy tools or steps
- Tastes great hot or cold
Servings: 6
Prep time: 15 minutes
Cook time: 35 minutes
Total time: 50 minutes
What You’ll Need
- 8 large eggs
- 1 cup whole milk
- 1 cup cherry tomatoes, halved
- 1 ½ cups fresh spinach, roughly chopped
- ¾ cup crumbled feta cheese
- ½ cup shredded mozzarella cheese
- ¼ cup onion, finely diced
- 1 clove garlic, minced
- 1 tablespoon olive oil
- ½ teaspoon salt
- ¼ teaspoon black pepper
- Butter or spray to grease the baking dish
- Optional: chopped parsley for garnish
Tools You’ll Need
- 8×12 baking dish
- Mixing bowl
- Whisk
- Frying pan
- Spatula
- Knife & cutting board
- Measuring cups and spoons
Pro Tips
- Let the casserole sit for 5–10 minutes before slicing so it holds together better.
- Use full-fat milk for fluffier texture and better flavor.
- Sautéing the onion and garlic first boosts the flavor—don’t skip it!
- Crumble the feta with your hands right before adding to keep it fluffy.
- Don’t overbake—pull it out when the center is just set.
Substitutions and Variations
- Swap spinach for kale or arugula
- Use cheddar or goat cheese instead of mozzarella or feta
- Add cooked bacon or sausage for a meatier version
- Use lactose-free milk or non-dairy milk like oat or almond (unsweetened)
- Add mushrooms or bell peppers for more veggies
Make-Ahead Tips
You can prep everything the night before—just cover and refrigerate the unbaked casserole. Bake it in the morning straight from the fridge, adding 5–10 minutes to the baking time.
Recipe & Instructions
Step 1: Preheat the oven & grease the dish
Preheat your oven to 375°F and grease a 9×9 baking dish with butter or spray.
Step 2: Sauté the onion and garlic
Heat 1 tablespoon olive oil in a frying pan. Add ¼ cup finely diced onion and 1 clove minced garlic. Sauté for 3–4 minutes until softened and fragrant.
Step 3: Whisk the eggs and milk
In a large mixing bowl, whisk together 8 large eggs and 1 cup whole milk until smooth.
Step 4: Add sautéed onion and garlic
Stir the sautéed onion and garlic into the egg mixture.
Step 5: Add veggies, feta, mozzarella, salt & pepper
Stir in 1 ½ cups chopped spinach, 1 cup halved cherry tomatoes, ¾ cup crumbled feta, ½ cup shredded mozzarella, ½ teaspoon salt, and ¼ teaspoon black pepper.
Step 6: Pour into baking dish
Pour the egg and veggie mixture into your greased 8×12 baking dish. Spread evenly.
Step 7: Bake
Place the dish in the oven and bake for 35 minutes at 375°F until the eggs are set and lightly golden on top.
Step 8: Cool and garnish
Let the casserole sit for 5–10 minutes after baking. Sprinkle with chopped parsley if you like.
Leftovers & Storage
Store leftovers in an airtight container in the fridge for up to 4 days. Reheat in the microwave or oven. You can also freeze slices individually—wrap tightly and freeze for up to 2 months.
Macros (Per Serving, based on 6 servings)
- Calories: 225
- Protein: 13g
- Carbs: 6g
- Fat: 16g
- Fiber: 1g
- Sugar: 3g
Why This Recipe Works (Quick Science)
Eggs set into a firm texture thanks to the proteins unfolding and bonding when heated. Whole milk adds moisture and richness, while feta and mozzarella melt at different rates, giving both creamy and stretchy textures. The veggies add water, but the bake time ensures it sets without turning watery.
Common Mistakes
- Not sautéing the onion and garlic first: Raw onion will overpower the dish.
- Overbaking: It dries out quickly—pull it when the center is just set.
- Not chopping the spinach: Leaves too big can cause soggy spots.
- Skipping the grease: Always butter or spray the dish to prevent sticking.
What to Serve With
- Crispy roasted potatoes
- Toast or crusty bread
- Simple arugula or cucumber salad
- Fresh fruit on the side
- A hot cup of coffee or fresh-squeezed juice
FAQ
Can I use frozen spinach?
Yes! Just thaw and squeeze out all the water before using.
Is it good cold?
Absolutely. It’s even great straight from the fridge.
Can I double the recipe?
Yep! Just use a 9×13 baking dish and increase bake time by about 10–15 minutes.
Can I make this dairy-free?
Use dairy-free milk and cheese substitutes. It still turns out great.
Final Thoughts
This breakfast casserole is cozy, simple, and full of fresh flavor. Whether you’re feeding a small crowd or just stocking your fridge with easy meals, it delivers every time. Give it a try, and let me know how it turned out for you in the comments!