This veggie breakfast casserole is an easy, wholesome way to pack vegetables into a protein-rich breakfast that works for both busy mornings and make-ahead meals. Made with simple ingredients like eggs, bell peppers, mushrooms, and spinach, it bakes up fluffy, flavorful, and satisfying without feeling heavy.
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A Quick Look at the Recipe
✅ Recipe Name: Veggie Breakfast Casserole
🕒 Ready In: ~40 minutes
👪 Serves: 6-8 servings
🍽 Calories: ~200 per serving (estimated)
🥣 Main Ingredients: Eggs, bell peppers, mushrooms, spinach, onion, cheddar cheese
📖 Dietary Info: Gluten-free; vegetarian
👌 Difficulty: Easy - simple prep with basic sautéing and baking
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Unlike many breakfast casseroles that rely on hash browns, bread, or complicated prep, this version keeps things straightforward and veggie-forward. The vegetables are sautéed first for better texture and flavor, then combined with a seasoned egg mixture and just enough cheese to hold everything together.
If you love quick, make-ahead breakfasts, try our Cookie Dough Overnight Oats, Feta Spinach Egg Muffins, or Strawberry Granola for an easy morning routine.
Jump to:
- A Quick Look at the Recipe
- Why You'll Love this Veggie Breakfast Casserole:
- Key Ingredients:
- Easy Substitutions & Variations:
- How to Make Veggie Breakfast Casserole:
- Recipe Notes & Tips:
- How to Store:
- Veggie Breakfast Casserole FAQs:
- More Breakfast Recipes You'll Love
- Get a FREE Healthy Meal Planning Ebook
- Veggie Breakfast Casserole
Why You'll Love this Veggie Breakfast Casserole:
Great for meal prep: This casserole can be made ahead and reheated easily, making busy mornings much simpler.
Vegetable-packed: Bell peppers, mushrooms, onions, and spinach add color, texture, and nutrients to every bite.
Protein-rich: Eggs provide a filling, balanced base that keeps you satisfied through the morning.
Simple ingredients: Made with everyday pantry and fridge staples, no specialty items needed.
Easy to customize: Swap in different vegetables or cheeses based on what you have on hand.
Key Ingredients:
- bell peppers. A mix of red and green adds sweetness and color. Orange or yellow can be used instead.
- mushrooms. White button mushrooms provide mild umami flavor. Baby bella or cremini are good alternatives.
- spinach. Fresh baby spinach wilts nicely into the casserole. If using frozen spinach, thaw and squeeze out excess moisture first.
- eggs. The base of the casserole. Large eggs are standard; don't reduce the number or the structure may suffer.
- cheddar cheese. Sharp or mild cheddar both melt well. Substitute with mozzarella, Monterey Jack, or a dairy-free cheese if needed.
Scroll to the recipe card at the bottom of this page for exact quantities.
Easy Substitutions & Variations:
- Add protein: Stir in cooked breakfast sausage, bacon, or diced ham for a heartier casserole.
- Change the vegetables: Swap the bell peppers and mushrooms for zucchini, broccoli, asparagus, or leftover roasted vegetables.
- Use a different cheese: Cheddar works well, but Monterey Jack, Colby Jack, or Swiss are great alternatives.
- Dairy-free option: Use Homemade Almond Milk and omit the cheese or replace it with a dairy-free alternative.
- Make it spicier: Add a pinch of red pepper flakes or diced jalapeño for a little heat.
How to Make Veggie Breakfast Casserole:
- Preheat the oven to 350 degrees. Spray a 9x13 baking dish with cooking spray and set aside.
- In a large skillet over medium heat, add the olive oil, onion, peppers, and mushrooms. Cook until vegetables soften and onions become translucent. Remove from heat.
- In the baking dish later the cooked vegetables, baby spinach and ¾ cup of cheddar cheese. Toss to mix then set aside.
- In a large mixing bowl, beat the eggs and milk until well combined. Stir in the garlic, salt and pepper.
- Pour the egg mixture evenly into the baking dish. Top with the rest of the cheddar cheese. Bake in the oven for 30 minutes or until the eggs are cooked through.
Recipe Notes & Tips:
- Sauté vegetables thoroughly: Cook until the peppers and mushrooms release their moisture to avoid a watery casserole.
- Layer spinach raw: There's no need to pre-cook the spinach, baking will wilt it perfectly.
- Mix cheese throughout: Stirring some cheese into the veggie layer ensures even flavor, while topping adds a golden finish.
- Whisk eggs well: Beat until fully blended for a uniform texture and better rise.
- Let it rest before slicing: Allow the casserole to cool for 5-10 minutes after baking so it sets and slices cleanly.
- Use a glass or ceramic dish: These materials help cook the casserole more evenly than metal pans.
How to Store:
Refrigerator: Let the casserole cool completely, then store in an airtight container in the fridge for up to 4 days.
Freezer: Slice into portions and wrap each tightly in plastic wrap or foil, then place in a freezer-safe bag or container. Freeze for up to 2 months.
Reheating: Warm in a 350°F oven for 10-15 minutes, or until heated through.
Veggie Breakfast Casserole FAQs:
Yes. You can assemble and bake the casserole up to one day in advance. Let it cool completely, cover, and refrigerate. Reheat gently in the oven or microwave before serving.
The casserole is done when the center is fully set and no longer jiggly. A knife inserted into the middle should come out mostly clean.
Absolutely. This recipe works well with many vegetables, including zucchini, broccoli, asparagus, or leftover roasted veggies. Just be sure to cook off excess moisture first.
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Veggie Breakfast Casserole
Ingredients
Instructions
- Preheat the oven to 350 degrees. Spray a 9x13 baking dish with cooking spray and set aside.
- In a large skillet over medium heat, add the olive oil, onion, peppers, and mushrooms. Cook until vegetables soften and onions become translucent. Remove from heat.
- In the baking dish later the cooked vegetables, baby spinach and ¾ cup of cheddar cheese. Toss to mix then set aside.
- In a large mixing bowl, beat the eggs and milk until well combined. Stir in the garlic, salt and pepper.
- Pour the egg mixture evenly into the baking dish. Top with the rest of the cheddar cheese. Bake in the oven for 30 minutes or until the eggs are cooked through.
Nutrition
Notes
- Sauté vegetables thoroughly: Cook until the peppers and mushrooms release their moisture to avoid a watery casserole.
- Layer spinach raw: There's no need to pre-cook the spinach, baking will wilt it perfectly.
- Mix cheese throughout: Stirring some cheese into the veggie layer ensures even flavor, while topping adds a golden finish.
- Whisk eggs well: Beat until fully blended for a uniform texture and better rise.
- Let it rest before slicing: Allow the casserole to cool for 5-10 minutes after baking so it sets and slices cleanly.
- Use a glass or ceramic dish: These materials help cook the casserole more evenly than metal pans.
Lisa says
I had family visiting from out of town for a wedding and this was a big hit. Super easy and tasty recipe.