Kick start your week with a Meatless Monday breakfast casserole that will surely make anyone rise and shine! Like a lush, colorful garden, this easy vegetarian breakfast casserole is bursting with delicious, savory, hearty flavors. Healthy, wholesome veggies ribbon through fluffy, cheesy eggs on a bed of a delightful breakfast staple, tasty tater tots. Everyone will surely be at the breakfast table for a plate of this filling, veggie-loaded breakfast casserole!



  • 1/2 cup cremini mushrooms, sliced
  • 1/2 yellow onion, diced
  • 1/2 tablespoon garlic, minced
  • 4 ounces fresh baby spinach
  • 1 tablespoon olive oil
  • 2/3 cup jarred roasted red peppers, diced
  • 8 eggs
  • salt and pepper, to taste
  • 2 cups shredded sharp cheddar cheese, divided
  • 16 ounces tater tots, frozen


  1. Preheat your oven to 350 degrees. Lightly grease a baking dish with nonstick cooking spray. Then line the baking dish with frozen tater tots.

  2. Wash and dry the produce. Dice the onions, then thinly slice the mushrooms and mince the garlic. Set aside.

  3. Remove the roasted red peppers from the jar and dice them into bite-sized pieces. Set aside.

  4. Place the baby spinach in a large microwave-safe bowl and microwave on high power for 30 seconds to one minute or until the leaves become wilted. Using two forks, separate the wilted leaves. Set aside.

  5. On medium-high heat, in a large skillet, pour a tablespoon of olive oil. Sauté the onions and mushrooms until tender. Add the garlic and cook until fragrant. Remove from heat and set aside.

  6. In another large bowl, whisk the eggs until the yolks and whites are thoroughly combined. Add salt and pepper. Next, mix in the sautéed onions, mushrooms, and garlic. Then add the roasted red peppers, followed by the baby spinach and half the cheddar cheese. Mix until well blended.

  7. Pour the egg mixture over the frozen tater tots. Sprinkle the casserole with the remaining cheddar cheese.

  8. Bake for 40-45 minutes or until the eggs are set and thoroughly cooked, and the top is golden brown. Serve immediately. Enjoy!


  • 9x13" baking dish
  • large microwave-safe bowl
  • large skillet
  • large bowl
  • whisk

Recipe Notes

Can I Make Vegetarian Breakfast Casserole Ahead of Time?

Vegetarian breakfast casserole is an easy make-ahead breakfast fit for a crowd. Simply prepare the casserole the night before and store it overnight in the refrigerator. Tightly cover with plastic wrap or tin foil. To bake, place the casserole in a non-preheated oven, uncovered. Bake until eggs are set.

Should I Thaw the Tater Tots Before Using Them?

No. Tater tots do not need to be precooked or thawed on the counter before preparing the casserole. Frozen tater tots can be placed directly into the baking dish from the bag.

I Don't Like Roasted Red Peppers. Can I Use Another Vegetable?

Absolutely! If you don't care for the lightly sweet charred flavor of roasted red peppers, feel free to swap them out with another vegetable, such as fresh tomatoes. Vegetable breakfast casserole is an extremely versatile dish—a blank canvas waiting to be prepared with your favorite chopped veggies. We recommend adding finely chopped broccoli, cauliflower, asparagus, leeks, or green peppers.

Related Reading

Wait a Minute! Is Cheese Vegetarian?

vegetarian breakfast casserole ingredients
Brittany Baxter/Oola

Not all cheese is vegetarian-friendly. Some types of cheese, mostly European cheeses, use an enzyme called rennet to help the cheese curdle, separating the curds and whey. Rennet is taken from the lining of a newborn calf's fourth stomach, making it unsuitable for vegetarians. However, many companies have replaced animal rennet with vegetarian or microbial rennet, producing some cheeses safe for vegetarian diets.

So, before you prepare your vegetarian breakfast casserole, check the ingredient list on your cheese and make sure it's vegetarian safe. When in doubt, purchase certified kosher cheeses, as the Jewish religion prohibits meat and dairy from being served or eaten together.

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