Ingredients You’ll Need

For the Vegetables:

  • 1 head of broccoli, cut into florets
  • 1 head of cauliflower, cut into florets
  • 1 red bell pepper, sliced
  • 1 yellow bell pepper, sliced
  • 1 cup cherry tomatoes, halved
  • 1/4 cup olive oil
  • 1 teaspoon Italian seasoning
  • 1/2 teaspoon salt
  • 1/4 teaspoon black pepper
  • 1 green Spanish onion, chopped
  • 1 cup chopped spinach leaves (optional)

For the Egg Mixture:

  • 4 large eggs
  • 1/2 cup milk (any kind – dairy or plant-based)
  • 1/4 cup all-purpose flour
  • 1/4 teaspoon salt
  • 1/4 teaspoon black pepper

Optional Toppings:

  • 1/2 cup shredded mozzarella or cheddar cheese (optional, for extra flavor)
  • A sprinkle of fresh herbs like parsley, basil, or thyme

Equipment Checklist

  • 1 large mixing bowl
  • 1 whisk or fork
  • 1 9×13-inch glass baking dish
  • Measuring cups and spoons
  • Oven and baking rack
  • Nonstick cooking spray or light brushing of oil

Step-by-Step Instructions

1. Preheat and Prepare

Preheat your oven to 375°F (190°C). Lightly grease your casserole dish with olive oil or nonstick spray to prevent sticking. This step ensures easy cleanup and perfectly released servings.

2. Prep the Vegetables

Wash all your vegetables thoroughly. Cut the broccoli and cauliflower into bite-sized florets. Slice the bell peppers and halve the cherry tomatoes. Chop the green onion and spinach if using. Having a mix of colors makes the dish visually stunning and ensures a range of nutrients.

3. Season and Toss

In a large bowl, combine all the chopped vegetables. Drizzle with olive oil, sprinkle the Italian seasoning, salt, and pepper, and toss well until every piece is lightly coated. This step infuses flavor before baking and ensures even roasting.

4. Arrange in the Baking Dish

Transfer the seasoned vegetables into your prepared casserole dish. Spread them evenly to form a colorful layer — this will be the heart of your casserole. The mix of broccoli, cauliflower, and peppers will create a beautiful mosaic once baked.

5. Prepare the Egg Mixture

In a separate bowl, whisk together the eggs, milk, flour, salt, and pepper until smooth. The flour helps the mixture thicken slightly, creating a soft, custard-like texture that holds the vegetables together without being too dense or heavy.

6. Pour and Combine

Slowly pour the egg mixture over the vegetables, ensuring it spreads evenly throughout the dish. Tilt the casserole dish gently to help the mixture seep into every corner, coating the vegetables.

7. Add Cheese (Optional)

If you’re including cheese, sprinkle it evenly over the top. Cheese adds richness and a delicious golden crust once baked, but you can easily omit it for a lighter version.

8. Bake to Perfection

Place the casserole dish in the preheated oven and bake for 35–40 minutes, or until the top is golden brown and the center is set. You’ll know it’s done when a knife inserted in the center comes out clean, and the cheese (if added) is beautifully melted.

9. Cool Slightly Before Serving

Allow the casserole to rest for 5–10 minutes after removing it from the oven. This helps it firm up slightly and makes slicing easier. The aroma of roasted vegetables and herbs will fill your kitchen — truly irresistible!

Serving Suggestions

This casserole is versatile and can be enjoyed in many ways:

  • Breakfast: Pair with avocado or a side of fruit for a protein-packed morning.
  • Lunch: Serve with a side of brown rice or quinoa for a complete meal.
  • Dinner: Enjoy with grilled chicken or fish for added protein.
  • Snack: Cut into small squares for a grab-and-go healthy bite.

Storage and Reheating Tips

  • Store leftovers in an airtight container in the refrigerator for up to 4 days.
  • To reheat, bake in a preheated oven at 350°F (175°C) for about 10 minutes, or microwave individual portions for 1–2 minutes.
  • You can also freeze the casserole in portions for up to 2 months. Reheat directly from frozen for a convenient meal anytime.