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A cheesy breakfast casserole in a white dish on a wooden table

The Best Breakfast Casserole Recipe for a Crowd

If you're looking for a breakfast that feeds many without the morning rush, this breakfast casserole is a solid pick. It’s warm, filling, and easy to prep ahead of time, perfect for holidays, lazy Sundays, and meal prep.
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Prep Time 30 minutes
Cook Time 45 minutes
Total Time 1 hour 15 minutes
Servings: 8 servings
Course: Breakfast, Brunch
Cuisine: American
Ingredients Method Notes

Ingredients
  

For the potatoes
  • 3 medium Yukon Gold potatoes (about 1 pound), diced small
  • 1 tablespoon olive oil
  • 0.5 teaspoon sea salt
  • to taste black pepper freshly ground
For the casserole
  • 12 large eggs
  • 1 cup milk any kind
  • 1.25 teaspoons sea salt divided
  • 2 tablespoons olive oil
  • 0.5 yellow onion chopped
  • 2 cloves garlic chopped
  • 1 red bell pepper chopped
  • 1 green bell pepper chopped
  • 1 cup fresh spinach chopped
  • 4 green onions sliced
  • 1.5 cups shredded cheddar cheese

Method
 

  1. Roast the potatoes: Heat oven to 425°F (220°C). Line a sheet pan with parchment paper. Toss diced potatoes with olive oil, salt, and pepper. Spread evenly and roast for 20–25 minutes until golden and tender.
  2. Prep the egg mix: In a bowl, whisk eggs, milk, and ¼ teaspoon salt.
  3. Cook the vegetables: In a skillet, warm olive oil over medium heat. Add onion and the rest of the salt. Cook until soft (about 5–8 minutes). Add garlic and both peppers. Cook for 2 minutes. Stir in spinach and half the green onions. Cook until wilted.
  4. Assemble: Lower oven to 350°F (175°C). Oil a 9x13 baking dish. Spread potatoes in a single layer. Top with 1 cup cheese, then vegetables. Pour the egg mix over everything. Sprinkle with the rest of the cheese and green onions.
  5. Bake: Bake for 40–45 minutes until the eggs are firm. Let sit 5 minutes before serving.

Notes

You can prepare the casserole fully the night before and bake in the morning, or prep the potatoes and veggies ahead and assemble later. Store leftovers in the fridge up to 3 days or freeze for 3 months. Reheat in the microwave or oven.
Optional: Add cooked sausage or turkey bacon to the layers if desired.