Spinach Frittata Casserole
The Spinach Frittata Casserole is a nourishing, protein-rich, oven-baked dish combining eggs, spinach, cheese, and aromatics into one wholesome meal. Unlike stovetop frittatas, this casserole-style version is hands-off once it’s in the oven—making it perfect for meal prep, brunches, or an easy weeknight dinner. It’s naturally gluten-free, customizable, and pairs beautifully with salads or toast.
Time Required
Preparation Time: 10 minutes
Cooking Time: 35 minutes
Cooling Time: 5 minutes
Total Time: 50 minutes
Servings: 6
Ingredients
10 large eggs
1 cup milk (whole, 2%, or dairy-free alternative like almond or oat)
1 tbsp olive oil or butter
½ medium onion, diced
2 cloves garlic, minced
5 oz fresh spinach (about 5 cups loosely packed)
1 cup shredded cheese (cheddar, mozzarella, feta, or a blend)
¼ tsp nutmeg (optional, enhances the spinach flavor)
Salt & pepper to taste
Optional add-ins:
½ cup diced bell pepper or mushrooms
½ cup cooked bacon, sausage, or chopped sun-dried tomatoes
2 tbsp chopped fresh herbs (parsley, dill, or basil)
Instructions
Preheat oven to 375°F (190°C). Lightly grease a 9×9-inch (or similar-sized) casserole dish.
Sauté the aromatics:
In a skillet over medium heat, add olive oil. Sauté diced onion for 3–4 minutes until translucent. Add garlic and cook for 30 seconds more.
Wilt the spinach:
Add spinach to the skillet (in batches if needed) and sauté until wilted, about 2–3 minutes. Remove from heat.
Prepare the egg mixture:
In a large bowl, whisk the eggs with milk, salt, pepper, and nutmeg. Stir in shredded cheese.
Combine and pour:
Add the spinach-onion mixture (and any optional add-ins) to the egg mixture. Mix well. Pour into the greased baking dish and smooth the top.
Bake:
Bake for 30–35 minutes or until the center is set and the top is lightly golden. A toothpick inserted in the center should come out clean.
Cool and serve:
Let rest for 5 minutes before slicing. Serve warm, at room temperature, or cold.
Tips
For extra fluffiness, use half-and-half instead of milk.
You can prep ahead: saute veggies the night before and assemble in the morning.
Use frozen spinach (thawed and well-drained) if fresh isn’t available—use about 1 cup.
Don’t overbake—check for doneness by gently jiggling the dish; it should be just set in the center.
Add hot sauce, salsa, or avocado on the side for extra flavor.
Notes
This casserole keeps in the fridge for up to 4 days.
It can be frozen in individual slices for up to 2 months. Reheat in microwave or oven.
Suitable for keto, low-carb, and gluten-free diets.
Great as a meal prep breakfast or brunch dish.
Frequently Asked Questions
Q: Can I make this dairy-free?
A: Yes! Use a plant-based milk (like oat or almond) and skip the cheese or use vegan cheese alternatives.
Q: Can I add potatoes or hash browns?
A: Yes—shredded cooked potatoes or hash browns can be added, but keep the egg ratio in mind. Add no more than ½ to ¾ cup.
Q: How do I know it’s done baking?
A: The center should be firm and puffed. Insert a knife or toothpick in the center—it should come out clean.
Q: Can I use egg whites only?
A: Yes, you can use 12 egg whites instead of whole eggs for a lower-fat version.
Q: What’s the difference between a frittata and a quiche?
A: A frittata has no crust and typically uses less dairy than a quiche. It’s lighter and more protein-focused.
Nutritional Information
Calories: 210
Protein: 15g
Fat: 14g
Saturated Fat: 5g
Carbohydrates: 6g
Fiber: 1g
Sugar: 2g
Sodium: 350mg
Calcium: 15% DV
Iron: 12% DV