This veggie-packed breakfast casserole is a perfect way to start your day with a smile. It’s filled with fresh vegetables, eggs, and cheese, making it both healthy and yummy!
Honestly, who doesn’t love a dish that brings all the flavors together in one big, comforting bite? I enjoy making this ahead of time and just reheating it for a busy morning. So easy!
Key Ingredients & Substitutions
Eggs: Eggs are the base for this dish, providing protein and structure. If you’re looking for an egg substitute, consider using aquafaba (the liquid from canned chickpeas) or flax eggs (1 tbsp flaxseed meal mixed with 2.5 tbsp water for each egg).
Milk: Whole or 2% milk adds creaminess. You can use non-dairy options like almond milk, soy milk, or oat milk, but make sure they are unsweetened to avoid altering the flavor.
Red Bell Pepper: This adds color and crunch! You can swap it for other peppers like orange or yellow for sweetness, or use zucchini or diced tomatoes for a different twist.
Mushrooms: For a rich flavor, I love using cremini or button mushrooms. If you’re not a fan, try replacing them with extra veggies like broccoli or finely chopped carrots.
Fresh Spinach: Spinach is a nutritious leafy green. Kale can be a great alternative if you prefer a sturdier greens option. Just remember to remove the tough stems.
How Can You Ensure Your Casserole is Perfectly Set?
Achieving the right texture is key. You want your casserole to be fluffy but firm. Here’s how to ensure it sets properly:
- Whisk eggs thoroughly with milk; this adds air and fluffiness.
- Make sure all vegetables are cooked and excess moisture is removed before adding to the egg mixture. This prevents a soggy casserole.
- Allow the casserole to cool for a few minutes before slicing. This helps it firm up further.
Following these tips will help you make a delicious and satisfying breakfast casserole that everyone will love!

Veggie-Packed Breakfast Casserole
Ingredients You’ll Need:
For the Casserole:
- 8 large eggs
- 1 cup milk (whole or 2%)
- 1 red bell pepper, diced
- 1 cup mushrooms, sliced
- 1 cup fresh spinach, chopped
- 1 small onion, diced
- 1 cup shredded cheese (cheddar, mozzarella, or a blend)
- 2 cloves garlic, minced
- 1 tbsp olive oil
- Salt and pepper, to taste
- Optional: 1/2 tsp dried thyme or oregano for extra flavor
How Much Time Will You Need?
This delicious breakfast casserole takes about 15 minutes of prep time and around 35-40 minutes to bake. Set aside about an hour in total for preparation and cooking. If you’re making it ahead of time, you can refrigerate it and simply reheat it in the morning!
Step-by-Step Instructions:
1. Preheat the Oven:
Start by preheating your oven to 350°F (175°C). While the oven is heating, get your casserole dish ready. Lightly grease or spray a 9×9-inch casserole dish to prevent sticking.
2. Sauté the Veggies:
In a large skillet, pour in the olive oil and heat it over medium heat. Add your diced onion and minced garlic, sautéing until they are translucent and fragrant, about 3-4 minutes. This will create a delicious base for your casserole!
3. Add More Vegetables:
Next, toss in the sliced mushrooms and diced red bell pepper. Continue cooking for another 5 minutes until the vegetables are tender. This adds great taste and texture to your dish.
4. Mix in Spinach:
Now, add the chopped spinach to the skillet. Cook until it’s wilted, which should only take about 1-2 minutes. Once done, remove the skillet from heat and set it aside to cool a bit.
5. Prepare the Egg Mixture:
In a large mixing bowl, whisk together the eggs, milk, salt, pepper, and any dried herbs you’re using. This will be the magic that holds everything together!
6. Combine and Stir:
Gently fold in the sautéed vegetables and shredded cheese into the egg mixture. Make sure everything is well combined for a lovely, flavorful bite in every piece!
7. Pour and Spread:
Pour your delicious mixture into the prepared casserole dish. Make sure to spread it evenly for even cooking.
8. Bake It Up:
Place your casserole in the preheated oven and bake for about 35-40 minutes. You’ll know it’s done when the egg is fully set and a knife inserted in the center comes out clean.
9. Let it Cool and Serve:
Once baked, remove the casserole from the oven and let it cool for a few minutes. Then, slice it up and serve warm. Enjoy your vibrant and nutritious veggie-packed breakfast casserole!
Happy cooking!
Can I Use Different Vegetables in This Casserole?
Absolutely! Feel free to get creative with your veggie choices. Zucchini, asparagus, broccoli, or even sweet potatoes work wonderfully. Just ensure that any veggies you use are cooked and have a similar cooking time to those listed in the recipe.
How Do I Store Leftovers?
Store any leftover casserole in an airtight container in the fridge for up to 3-4 days. It reheats well in the microwave or oven—just cover it with foil to maintain moisture while warming it up.
Can I Make This Casserole Ahead of Time?
Yes! You can prepare the entire casserole the night before, cover it with foil, and refrigerate. Just pop it in the oven in the morning, adding an extra 5-10 minutes to the baking time since it will be cold.
What Can I Serve With This Breakfast Casserole?
This casserole pairs great with fresh fruit, yogurt, or a simple green salad. For a heartier breakfast, consider serving it with toast or a side of breakfast potatoes!


