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Vegetarian Breakfast Casserole 1

Vegetarian Breakfast Casserole

This protein-rich Vegetarian Breakfast Casserole combines eggs with nutrient-dense vegetables for a complete morning meal that keeps you fueled for hours. Perfect for weekend brunches or meal prepping for busy weekdays, you can assemble it the night before and simply bake in the morning for a stress-free, nutritious start to your day.
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Prep Time 20 minutes
Cook Time 50 minutes
Resting Time 30 minutes
Total Time 1 hour 40 minutes
Course Breakfast, Brunch
Cuisine American, Vegetarian
Servings 8 servings
Calories 320 kcal

Equipment

  • 9x13-inch Baking Dish
  • Large Skillet
  • Mixing Bowl
  • Whisk

Ingredients
  

For the Base

  • 12 large eggs preferably organic for richer flavor
  • 1 cup milk dairy or plant-based both work
  • 2 cups shredded cheese sharp cheddar, fontina, or gruyère recommended
  • 8 cups day-old bread cubed (sourdough works well)
  • 2 tablespoons olive oil

For the Vegetables

  • 2 cups fresh spinach roughly chopped
  • 1 red bell pepper diced
  • 1 medium yellow onion finely diced
  • 2 cloves garlic minced
  • 1 cup mushrooms sliced (cremini or shiitake recommended)
  • 1 cup cherry tomatoes halved

For Seasoning

  • 1 teaspoon dried herbs thyme, rosemary, and oregano blend
  • 1/2 teaspoon smoked paprika
  • salt to taste
  • freshly ground black pepper to taste
  • pinch red pepper flakes optional, for heat

Instructions
 

  • Heat olive oil in a large skillet over medium heat. Add the diced onions and sauté for 3-4 minutes until translucent. Add the garlic and cook for another 30 seconds until fragrant.
  • Add bell peppers and mushrooms to the skillet, cooking for 5-6 minutes until peppers soften and mushrooms release moisture. Season with half of your dried herbs, salt, and pepper. Add spinach in the last minute and cook just until wilted. Remove from heat and let cool slightly.
  • In a large bowl, whisk together eggs, milk, remaining herbs, smoked paprika, and red pepper flakes (if using) until well combined with no visible egg white streaks.
  • Grease a 9×13-inch baking dish with olive oil or cooking spray. Layer half the bread cubes on the bottom, followed by half the vegetable mixture and half the cheese. Repeat with remaining bread, vegetables, and most of the cheese (reserve about ¼ cup for topping).
  • Slowly pour the egg mixture over the layered ingredients, ensuring all bread cubes get soaked. Gently press down with a spatula to help absorption. Let sit for at least 30 minutes (or refrigerate overnight covered with plastic wrap).
  • Preheat oven to 350°F (175°C). If refrigerated, let the casserole sit at room temperature for 30 minutes before baking. Sprinkle with reserved cheese and halved cherry tomatoes.
  • Bake uncovered for 45-50 minutes, until the center is set and the top is golden brown. A knife inserted in the center should come out clean with no runny egg mixture.
  • Let rest for 5-10 minutes before cutting into portions and serving.

Notes

For maximum flavor, assemble the casserole the night before and refrigerate overnight to allow the bread to fully absorb the egg mixture and the flavors to develop.
This casserole freezes well. Cut into individual portions after cooling completely, wrap in parchment paper and foil, and freeze for up to 2 months.
For a lower-carb option, replace bread with roasted cauliflower florets. For a higher protein version, add ½ cup of cottage cheese to the egg mixture.

Nutrition

Calories: 320kcalCarbohydrates: 22gProtein: 18gFat: 18gFiber: 3gVitamin A: 25IUVitamin C: 45mgCalcium: 30mgIron: 15mg
Keyword Vegetarian Breakfast, Egg Casserole, Breakfast Casserole, Meal Prep Breakfast, Make Ahead Breakfast
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