Sheet Pan Breakfast Casserole for a Crowd

A Crowd-Pleasing Breakfast Without the Stress

Feeding a crowd in the morning can feel overwhelming. Whether it’s a holiday gathering, a family reunion, a school event, or a busy weekend with guests, breakfast often becomes the most challenging meal to plan. People wake up at different times, everyone has different preferences, and the last thing you want to do is stand over the stove cooking multiple dishes while others are waiting to eat.

That’s where a sheet pan breakfast casserole truly shines. This recipe is designed to serve a large group efficiently, comfortably, and deliciously. Everything bakes together in one large pan, creating evenly cooked portions that are easy to slice and serve. There’s no juggling multiple skillets, no complicated timing, and no stress.

This casserole is hearty, satisfying, and built with simple, familiar ingredients that appeal to a wide range of tastes. It’s warm, comforting, and dependable—the kind of dish you can confidently place on the table knowing it will be enjoyed by everyone.

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Why a Sheet Pan Breakfast Casserole Is Perfect for a Crowd

When cooking for many people, efficiency and reliability matter just as much as flavor. A sheet pan breakfast casserole offers both.

First, the large surface area of a sheet pan allows the casserole to bake evenly. Each slice cooks at the same rate, so you don’t end up with overcooked edges and undercooked centers.

Second, it’s easy to portion. Once baked, the casserole can be cut into uniform squares, making serving fast and fair.

Third, it simplifies planning. One dish replaces several breakfast items, reducing prep time, cleanup, and stress.

Finally, it creates a welcoming, communal feel. Serving a big pan of warm, homemade breakfast encourages people to gather, relax, and enjoy the moment together.

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What Makes This Sheet Pan Breakfast Casserole Stand Out

Designed Specifically for Large Groups

This recipe is scaled intentionally for a crowd. It fills a standard sheet pan and yields generous portions without feeling skimpy.

Even Baking Every Time

The thinner, wider layer ensures consistent texture and doneness across the entire pan.

Familiar, Comforting Flavors

Nothing too bold or polarizing—just balanced seasoning and classic breakfast ingredients that most people love.

Minimal Cleanup

One pan in the oven means fewer dishes afterward, which is especially valuable when hosting.

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Ingredients for Sheet Pan Breakfast Casserole

Main Ingredients

• 18 large eggs

• 2 cups milk or unsweetened dairy-free milk

• 3 tablespoons olive oil or avocado oil

• 2 large onions, finely chopped

• 2 bell peppers, diced

• 2 cups mushrooms, sliced

• 2 cups spinach or kale, chopped

• 3 cups cooked potatoes or sweet potatoes, diced

• 1½ to 2 cups shredded cheese (optional, adjust to preference)

Simple Seasonings

• 2 teaspoons salt, or to taste

• 1½ teaspoons black pepper

• 2 teaspoons garlic powder

• 1½ teaspoons onion powder

• 1½ teaspoons paprika

• 1 teaspoon dried oregano or thyme

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Ingredient Breakdown: Built for Flavor and Balance

Eggs: The Backbone of the Dish

Eggs provide structure, protein, and richness. In a sheet pan casserole, they form a sturdy but tender base that holds everything together and slices cleanly for serving.

Potatoes: Hearty and Crowd-Friendly

Cooked potatoes help bulk up the casserole, making it more filling and ideal for serving many people. They add comfort and familiarity that guests appreciate.

Vegetables: Color, Texture, and Nutrition

A mix of onions, peppers, mushrooms, and greens adds depth of flavor and visual appeal. These vegetables also balance the richness of the eggs and make the dish feel complete.

Milk: Moisture and Softness

Milk ensures the eggs bake into a tender, fluffy texture instead of becoming dense or dry.

Cheese: Optional Crowd-Pleasing Comfort

Cheese adds richness and a golden top, but the casserole is still delicious without it, making it flexible for different preferences.

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Preparing the Sheet Pan for Success

Before assembling the casserole, it’s important to prepare your pan correctly.

Use a standard rimmed sheet pan. Line it with parchment paper or grease it generously with oil to prevent sticking and ensure easy cleanup.

Preheat your oven to 375°F (190°C) so it’s fully ready when the casserole goes in. Even heat is key to consistent baking.

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Step-by-Step Instructions

Cook the Vegetables First

Heat olive oil in a large skillet over medium heat. Add the chopped onions and cook until soft and lightly golden. Add bell peppers and mushrooms, cooking for 7 to 10 minutes until tender and most of the moisture has evaporated. Stir in spinach or kale and cook just until wilted. Remove from heat and allow to cool slightly.

Prepare the Egg Mixture

In a very large bowl, whisk together eggs and milk until fully combined. Add salt, black pepper, garlic powder, onion powder, paprika, and dried herbs. Whisk thoroughly to distribute seasoning evenly.

Assemble the Casserole

Spread the cooked vegetables evenly across the prepared sheet pan. Scatter the cooked potatoes evenly over the vegetables. Pour the egg mixture over everything, using a spatula if needed to ensure even coverage. Sprinkle cheese evenly on top if using.

Bake Until Set and Golden

Place the sheet pan in the oven and bake for 35 to 45 minutes, or until the center is fully set and the top is lightly golden. Rotate the pan halfway through baking for even cooking.

Rest Before Slicing

Allow the casserole to rest for 10 to 15 minutes before slicing. This helps it firm up and makes serving easier.

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Tips for Perfect Results When Cooking for a Crowd

Cook Vegetables Thoroughly

Removing excess moisture from vegetables prevents a watery casserole and improves texture.

Use a Large Bowl

Mixing eggs for a crowd requires space. A large bowl ensures even seasoning and easier pouring.

Don’t Overfill the Pan

Make sure ingredients are evenly distributed and not piled too thickly, which could affect baking time.

Resting Is Essential

Cutting too soon can cause the casserole to fall apart. Resting allows clean, neat slices.

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Customization Options for Different Groups

Vegetarian-Friendly as Written

This casserole is naturally vegetarian and satisfying, making it suitable for many dietary preferences.

Extra Protein Without Pork

Add cooked lentils, chickpeas, or grilled chicken breast for additional protein while keeping the dish inclusive.

Dairy-Free Version

Use dairy-free milk and omit cheese or use a dairy-free alternative. The casserole still bakes beautifully.

Mild or Bold Flavor Adjustments

Keep seasoning simple for a broad audience, or add herbs and spices if your group enjoys stronger flavors.

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Make-Ahead Tips for Events and Holidays

Assemble in Advance

You can assemble the entire casserole the night before, cover it tightly, and refrigerate. Bake fresh in the morning for minimal stress.

Bake Ahead and Reheat

Bake fully, cool, and refrigerate. Reheat in the oven at 350°F until warmed through before serving.

Transporting the Casserole

This dish travels well. Keep it covered and warm, or reheat at your destination.

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Storage and Leftovers

Refrigerator Storage

Store leftovers in airtight containers for up to four days.

Freezing Portions

Slice into portions and freeze for up to two months. Thaw overnight before reheating.

Reheating Tips

Reheat in the oven for large portions or the microwave for individual servings. Cover loosely to retain moisture.

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Serving Suggestions for a Crowd

Serve this sheet pan breakfast casserole straight from the pan for a casual, welcoming presentation. Pair it with fresh fruit, yogurt, bread, or a light salad to round out the meal.

It works equally well for brunch tables, buffet-style gatherings, or family-style meals where everyone serves themselves.

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Why This Recipe Works So Well for Gatherings

When hosting, reliability matters. This casserole delivers consistent results, generous servings, and familiar flavors that appeal to all ages.

It frees you from the kitchen, allowing you to focus on guests, conversation, and enjoying the occasion rather than managing multiple dishes.

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Common Mistakes to Avoid

• Skipping the vegetable cooking step

• Using too much liquid

• Overbaking until dry

• Cutting before resting

• Under-seasoning such a large batch

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Frequently Asked Questions

How many people does this sheet pan breakfast casserole serve?

It typically serves 12 to 16 people, depending on portion size.

Can I make this casserole the night before?

Yes, it can be fully assembled and refrigerated overnight before baking.

Does it reheat well for a crowd?

Yes, it reheats evenly and maintains good texture.

Can I serve it cold?

Yes, but it’s best enjoyed warm.

Is this recipe kid-friendly?

Yes, the flavors are mild and familiar, making it suitable for kids.

Can I adjust the vegetables?

Absolutely. Use vegetables your group enjoys or what you have available.

Is cheese required?

No, the casserole is still flavorful and set properly without cheese.

How do I know it’s fully cooked?

The center should be firm and a knife inserted should come out clean.

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Final Thoughts

This sheet pan breakfast casserole for a crowd is the ultimate solution for feeding many people with confidence and ease. It’s warm, hearty, and dependable—everything a group breakfast should be.

With one pan, simple ingredients, and straightforward preparation, it allows you to focus on what truly matters: bringing people together and enjoying the moment. Whether it’s a holiday morning, a family gathering, or a busy event, this casserole ensures everyone starts the day satisfied and well-fed.