Herbalicious Breakfast Casserole is a flavor-packed, make-ahead brunch dish that elevates the standard breakfast casserole with an abundance of fresh herbs and vegetables. This savory bake features layers of crusty bread, sautéed vegetables, cheese, and eggs infused with a medley of fresh herbs like basil, parsley, dill, and chives that give it incredible aromatic depth. Unlike heavy, meat-laden breakfast casseroles, this version is lighter and more refined while still being satisfying and substantial. Perfect for holiday brunches, weekend gatherings, or meal prep for the week, this casserole can be assembled the night before and baked fresh in the morning, filling your kitchen with irresistible aromas. It’s the kind of dish that impresses guests with its sophisticated flavors while requiring minimal morning effort, making you look like a culinary genius even if you’re barely awake.
Serving Quantity: 8 servings
Preparation Time: 20 minutes
Cooking Time: 45 minutes
Total Time: 9 hours 5 minutes (including overnight refrigeration)
Ingredients:
- 8 cups cubed bread (day-old sourdough or French bread, cut into 1-inch cubes)
- 10 large eggs
- 2 cups whole milk
- 1 cup heavy cream
- 2 tablespoons olive oil
- 1 large onion (diced)
- 2 cups fresh spinach (chopped)
- 1 red bell pepper (diced)
- 1 cup mushrooms (sliced)
- 3 cloves garlic (minced)
- 2 cups shredded gruyere or Swiss cheese
- 1 cup shredded sharp cheddar cheese
- Half cup fresh basil (chopped)
- Half cup fresh parsley (chopped)
- Quarter cup fresh dill (chopped)
- Quarter cup fresh chives (chopped)
- 2 teaspoons Dijon mustard
- 1 teaspoon salt
- Half teaspoon black pepper
- Quarter teaspoon nutmeg
- Butter (for greasing pan)
Nutrition Information (Per Serving):
- Calories: 485
- Protein: 24g
- Carbohydrates: 28g
- Fat: 30g
- Sugar: 6g
- Sodium: 745mg
- Fiber: 3g
- Cholesterol: 295mg
- Calcium: 425mg
- Iron: 3mg
1. Prepare the Bread
Cut the bread into one-inch cubes. Day-old or slightly stale bread works best because it absorbs the egg mixture without becoming too soggy. If your bread is fresh, spread the cubes on a baking sheet and toast in a 300-degree oven for 10 to 15 minutes until slightly dried out but not browned. Let the bread cool completely. Using crusty artisan bread like sourdough, French bread, or ciabatta gives the best texture and flavor. Avoid soft sandwich bread which becomes too mushy. Place the bread cubes in a large bowl and set aside.
2. Sauté the Vegetables
Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 5 minutes until softened and translucent. Add the diced red bell pepper and sliced mushrooms. Cook for another 5 to 6 minutes, stirring occasionally, until the vegetables are tender and the mushrooms have released their moisture and browned slightly. Add the minced garlic and chopped spinach. Cook for 2 minutes until the garlic is fragrant and the spinach has wilted completely. Season with a pinch of salt and pepper. Remove from heat and let the vegetable mixture cool slightly. This sautéing step concentrates flavors and removes excess moisture that would otherwise make the casserole watery.
3. Make the Egg Custard Base
In a large mixing bowl, whisk together the eggs, whole milk, and heavy cream until smooth and well combined. The mixture should be pale yellow and slightly frothy. Add the Dijon mustard, salt, black pepper, and nutmeg. Whisk again until everything is thoroughly incorporated. The mustard adds subtle tang and depth, while the nutmeg provides a classic French touch that enhances the cheese and eggs. This custard is what binds everything together and gives the casserole its creamy, custardy interior.
4. Add Herbs and Cheese
Add all the chopped fresh herbs to the egg mixture – the basil, parsley, dill, and chives. Stir well to distribute the herbs evenly throughout the custard. The abundance of fresh herbs is what makes this casserole “herbalicious” and sets it apart from ordinary breakfast bakes. Reserve half a cup of the shredded cheese for topping, then add the remaining gruyere and cheddar to the egg mixture. Stir to combine. The combination of gruyere and cheddar provides both nutty sophistication and sharp, familiar flavor.
5. Assemble the Casserole
Generously butter a 9 by 13 inch baking dish. Add the bread cubes to the dish, spreading them in an even layer. Scatter the cooled sautéed vegetables over the bread, distributing them evenly. Pour the egg and herb mixture over the bread and vegetables, making sure to pour it evenly across the entire dish. Use a spatula or your hands to press down on the bread gently, ensuring all the cubes are soaked with the egg mixture. Some bread should peek above the surface, which will get crispy during baking. Sprinkle the reserved cheese over the top.
6. Refrigerate Overnight
Cover the baking dish tightly with plastic wrap or aluminum foil. Refrigerate for at least 8 hours or overnight. This resting time is crucial as it allows the bread to fully absorb the egg custard, creating a cohesive, custardy texture throughout rather than soggy bottom with dry top. The flavors also meld together during this time. Don’t skip this step or rush it. The overnight soak transforms the casserole from good to exceptional. You can refrigerate for up to 24 hours if needed.
7. Bake Until Golden
When ready to bake, remove the casserole from the refrigerator and let it sit at room temperature for 20 to 30 minutes while the oven preheats. Preheat the oven to 350 degrees Fahrenheit. Remove the covering and bake uncovered for 45 to 50 minutes until the top is golden brown and puffed, the edges are crispy, and a knife inserted in the center comes out mostly clean. The center should be set but still slightly creamy, not dried out. If the top browns too quickly, tent loosely with foil for the last 15 minutes. Let the casserole rest for 10 minutes before cutting and serving.
Tips for Perfect Herbalicious Breakfast Casserole
Use a variety of fresh herbs for the most complex flavor. The combination suggested is ideal, but you can customize based on what’s available or your preferences. Avoid dried herbs as they don’t provide the same fresh, vibrant flavor.
Day-old bread is key to proper texture. Fresh bread absorbs too much liquid and becomes gummy. Stale bread creates the right balance of custardy interior and crispy edges.
Don’t skip the overnight refrigeration. This step is what transforms a pile of ingredients into a cohesive, restaurant-quality casserole. The bread needs time to soak.
Gruyere cheese adds sophisticated, nutty flavor that elevates this beyond typical breakfast casseroles. If you can’t find it, substitute fontina, Swiss, or more cheddar.
Customize the vegetables based on season and preference. Zucchini, asparagus, sun-dried tomatoes, or roasted red peppers all work beautifully. Just make sure to cook out excess moisture first.
For a meat version, add cooked bacon, sausage, or ham. Cook and crumble the meat, then layer it with the vegetables. The herby base pairs well with smoky meats.
This casserole reheats beautifully. Cut into portions and store in the refrigerator for up to 4 days. Reheat individual servings in the microwave or oven.
Freeze unbaked casserole for up to 2 months. Wrap tightly in plastic then foil. Thaw overnight in the refrigerator before baking as directed.
For a lighter version, use half and half instead of cream, reduce cheese by half, and increase vegetables. You can also use egg substitute for some of the whole eggs.
The casserole should puff up during baking like a soufflé but will deflate slightly as it cools. This is normal and doesn’t affect the taste.
Serve with fresh fruit, a simple green salad, or roasted tomatoes for a complete brunch. It’s rich enough that sides should be light and fresh.
Make individual portions in muffin tins for portion control or easy serving at buffets. Reduce baking time to 20 to 25 minutes for muffin-sized portions.
Fresh herbs make all the difference. If you must use dried, use only one-third the amount called for and add them to the egg mixture rather than the vegetables.
Let guests customize toppings. Offer hot sauce, salsa, sour cream, avocado, or extra fresh herbs on the side for personalizing each serving.
Use a serrated knife to cut clean squares. Wipe the knife between cuts for the neatest presentation. The first piece is always hardest to remove.
This casserole is naturally vegetarian but packed with protein from eggs and cheese. Add white beans for extra protein and fiber if desired.
Try different cheese combinations. Feta and sun-dried tomato, goat cheese and caramelized onion, or smoked gouda and mushroom all create unique flavor profiles.
The mustard in the custard is subtle but important. It adds depth and helps emulsify the eggs and dairy for smoother texture. Don’t omit it.
Bring the casserole to room temperature before baking for more even cooking. Cold casserole straight from the fridge takes longer and cooks unevenly.
Garnish with extra fresh herbs just before serving. The bright green herbs on golden brown casserole look beautiful and add a final burst of fresh flavor.
