Spinach Breakfast Casserole: Healthy & Veggie-Packed

This spinach breakfast casserole is the kind of dish that makes mornings easier and a lot tastier. It’s hearty, bright with veggies, and packed with protein to keep you full for hours. You can prep it the night before, bake it once, and enjoy leftovers all week.

It also works for a crowd, so it’s perfect for brunch or holiday mornings. Simple ingredients, minimal effort, and big flavor—that’s the goal here.

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Spinach Breakfast Casserole: Healthy & Veggie-Packed

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Prep Time 15 minutes mins

Cook Time 35 minutes mins

Total Time 50 minutes mins

Servings 6 servings

Ingredients

  

• 10 large eggs
• 2 cups fresh baby spinach (lightly packed; about 3–4 cups if using raw, it wilts down)
• 1 cup low-fat cottage cheese or plain Greek yogurt
• 1/2 cup milk (dairy or unsweetened almond milk)
• 1 cup shredded cheese (cheddar, mozzarella, or Monterey Jack)
• 1 red bell pepper, diced
• 1/2 medium yellow onion, diced
• 1 cup mushrooms, sliced
• 1 clove garlic, minced
• 2 tablespoons olive oil or avocado oil
• 1/2 teaspoon kosher salt (plus more to taste)
• 1/4 teaspoon black pepper
• 1/2 teaspoon smoked paprika (optional)
• 1/4 teaspoon red pepper flakes (optional, for a little heat)
• Fresh herbs like parsley or chives, chopped (optional, for garnish)
• Cooking spray or a little extra oil for the baking dish

Instructions

 

• Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9x13-inch baking dish with cooking spray or oil.
• Sauté the veggies: Warm the olive oil in a large skillet over medium heat. Add onion and mushrooms with a pinch of salt. Cook 4–5 minutes until softened and most moisture cooks off.
• Add pepper and spinach: Stir in the bell pepper and cook 2 minutes. Add garlic and cook 30 seconds. Add spinach in batches, stirring until wilted. Remove from heat and let cool slightly.
• Whisk the egg mixture: In a large bowl, whisk eggs, cottage cheese (or Greek yogurt), milk, salt, pepper, and smoked paprika. Mix until mostly smooth; small curds from cottage cheese are fine.
• Add cheese and vegetables: Fold in half the shredded cheese and the cooked vegetables. Taste a small spoonful and adjust salt if needed.
• Assemble: Pour the mixture into the prepared baking dish. Sprinkle the remaining cheese over the top. Add red pepper flakes if using.
• Bake: Place on the center rack and bake 28–35 minutes, until the edges are set and the center barely jiggles. A knife inserted near the center should come out mostly clean.
• Rest and serve: Let the casserole rest 10 minutes before slicing. Garnish with chopped parsley or chives if you like.

What Makes This Special

This casserole focuses on vegetables and lean protein without feeling skimpy. It’s light yet satisfying, and it bakes into soft, custardy eggs with a golden top.

You can swap ingredients based on what you have, which makes it a reliable go-to recipe. It also reheats well, so it’s ideal for meal prep and busy weekdays.

• Veggie-forward: Loaded with spinach, peppers, onions, and mushrooms for color and nutrients.
• High in protein: Eggs and cottage cheese or Greek yogurt add a creamy, protein-rich base.
• Make-ahead friendly: Assemble the night before and bake in the morning.
• Customizable: Easy to make dairy-free, gluten-free, or meat-free.

What You’ll Need

• 10 large eggs
• 2 cups fresh baby spinach (lightly packed; about 3–4 cups if using raw, it wilts down)
• 1 cup low-fat cottage cheese or plain Greek yogurt
• 1/2 cup milk (dairy or unsweetened almond milk)
• 1 cup shredded cheese (cheddar, mozzarella, or Monterey Jack)
• 1 red bell pepper, diced
• 1/2 medium yellow onion, diced
• 1 cup mushrooms, sliced
• 1 clove garlic, minced
• 2 tablespoons olive oil or avocado oil
• 1/2 teaspoon kosher salt (plus more to taste)
• 1/4 teaspoon black pepper
• 1/2 teaspoon smoked paprika (optional)
• 1/4 teaspoon red pepper flakes (optional, for a little heat)
• Fresh herbs like parsley or chives, chopped (optional, for garnish)
• Cooking spray or a little extra oil for the baking dish

Step-by-Step Instructions

1. Preheat and prep: Heat your oven to 375°F (190°C). Lightly grease a 9×13-inch baking dish with cooking spray or oil.
2. Sauté the veggies: Warm the olive oil in a large skillet over medium heat.

   Add onion and mushrooms with a pinch of salt. Cook 4–5 minutes until softened and most moisture cooks off.

3. Add pepper and spinach: Stir in the bell pepper and cook 2 minutes. Add garlic and cook 30 seconds.

   Add spinach in batches, stirring until wilted. Remove from heat and let cool slightly.

4. Whisk the egg mixture: In a large bowl, whisk eggs, cottage cheese (or Greek yogurt), milk, salt, pepper, and smoked paprika. Mix until mostly smooth; small curds from cottage cheese are fine.
5. Add cheese and vegetables: Fold in half the shredded cheese and the cooked vegetables.

   Taste a small spoonful and adjust salt if needed.

6. Assemble: Pour the mixture into the prepared baking dish. Sprinkle the remaining cheese over the top. Add red pepper flakes if using.
7. Bake: Place on the center rack and bake 28–35 minutes, until the edges are set and the center barely jiggles.

   A knife inserted near the center should come out mostly clean.

8. Rest and serve: Let the casserole rest 10 minutes before slicing. Garnish with chopped parsley or chives if you like.

Keeping It Fresh

• Refrigerate: Cool completely, then cover and refrigerate for up to 4 days. Store as whole squares or in meal-prep containers.
• Reheat: Microwave individual portions 45–60 seconds, or rewarm in a 300°F (150°C) oven for 10–12 minutes.
• Freeze: Cut into squares, wrap tightly, and freeze for up to 2 months.

  Thaw overnight in the fridge, then reheat as above.

• Moisture watch: If condensation forms, dab the surface with a paper towel before reheating to keep the texture light.

Health Benefits

• Protein for steady energy: Eggs and cottage cheese help keep you full and support muscle repair after workouts.
• Iron and folate from spinach: These nutrients support red blood cell function and overall energy.
• Antioxidants from colorful veggies: Bell peppers and spinach bring vitamins A and C, which support immune health.
• Calcium for bones: Dairy adds a boost of calcium. If you go dairy-free, use a fortified plant milk.
• Fiber for digestion: Vegetables add bulk and fiber, helping you feel satisfied without heaviness.

Common Mistakes to Avoid

• Skipping the sauté: Raw mushrooms and onions release water and can make the casserole watery. Cook them first.
• Overbaking: This leads to dry, spongy eggs.

  Pull it when the center is just set and let carryover heat finish the job.

• Too much cheese on top: A heavy layer can weigh it down. Use half inside and half on top for balance.
• Not seasoning the base: Eggs need salt. Taste the mixture before baking and adjust as needed.
• Using a small pan: Overcrowding extends bake time and can cause uneven cooking.

  Stick to a 9×13-inch dish or split into two smaller pans.

Alternatives

• Dairy-free: Use unsweetened almond or oat milk and skip the cottage cheese and shredded cheese. Add 1–2 tablespoons nutritional yeast for a savory boost.
• Meat add-ins: Cooked turkey sausage, chicken sausage, or lean bacon bits work well. About 1 cup, crumbled or chopped.
• Veggie swaps: Try kale, zucchini (sauté first), or broccoli florets (steam or sauté to soften).

  Sun-dried tomatoes add a nice tang.

• Spice it up: Add diced jalapeño, chipotle powder, or a pinch of cayenne. A swirl of hot sauce on top is great too.
• Gluten-free and low-carb: This recipe already fits both. If you want more bulk, add diced roasted sweet potato or cauliflower rice.
• Cheese choices: Feta adds briny pop, goat cheese gives creaminess, and pepper jack brings heat.