Easy Vegetarian Tater Tot Breakfast Casserole

An irresistible breakfast hot dish that’s quick to prepare, packed with vibrant veggies, cheese, and eggs poured over a tater tot base. This vegetarian tater tot breakfast casserole takes just 20 minutes to assemble but also feeds a crowd and makes meal prep a breeze.

I’ve tested this recipe dozens of times and my taste testers have raved about it each and every time, your family and friends will too. The perfect breakfast hot dish to bring to your next pot luck.

I enjoy giving precise details in my recipe posts to lead my readers through any questions. If you’re just here for the printable recipe, use the Jump to Recipe to head straight there!

While testing this tater tot casserole without meat recipe, I tried sauteing the onions and mushrooms and adding the rest of the veggies raw to the egg mixture. This yielded an egg casserole with more of a crispy veggie, crunchy bite.

My testers and I agreed it was better when sauteing all of the veggies ahead of time, they cook at an even rate in the egg casserole, with incredible flavors added to your breakfast bake.

Key Ingredients 

Butter or Oil | Use butter or cooking spray to prepare the baking dish and butter or olive oil to saute the onions and mushrooms.

Tater tots | Use frozen tater tots. I like the organic crispy tater tots, but you can use your favorite brand.

Milk and Cream | Make a creamy egg mixture to bind all the ingredients with a base of whole milk and heavy cream. If you substitute half and half or lower percentages of milk, your egg casserole may come out more runny than you hoped. See how to fix it.

Eggs | I always use large eggs for consistency in my baking and cooking. 

Seasonings | Season the egg mixture with kosher salt, smoked paprika, and black pepper to taste. If desired, include spicy cayenne pepper, too!

Veggies | Pack this vegetarian dish with fresh veggies, including onion, sliced mushrooms, bell peppers, and zucchini. Use your favorite mushrooms – I used Baby Bella mushrooms. Use your favorite peppers; I used red bell pepper, orange and yellow. You can use green bell peppers or your favorite colors. 

Cheese | Use shredded cheeses like Pepper Jack or Monterey Jack cheese and cheddar cheese. I used white sharp white cheddar and Pepper Jack, but any combination will do.

Garnish | Sprinkle the finished casserole with chopped fresh basil or Italian parsley. Include sliced green onions, too, if desired.

How to Make Easy Vegetarian Breakfast Casserole 

Step 1 | Prep and Saute Veggies

First, preheat the oven to 350°F (175° C) and spray or butter a 9×13-inch baking dish, lining the frozen tater tots in an even layer on the bottom. I like using butter, cause…butter!

Heat the butter or oil over medium heat in a large skillet. Once the oil shimmers, add the diced onions, peppers, and zucchini, sauteing until they soften and brown slightly, stirring occasionally, about 5-7 minutes.

Then, toss in the sliced mushrooms, and continue to saute for 3-4 more minutes until the mushrooms are softened and browned.

Allow the vegetable mixture to cool for a few minutes so you don’t cook your eggs when you add the egg mixture. 

Step 2 | Make Egg Mixture

Meanwhile, beat eggs in a large bowl until smooth, adding kosher salt, smoked paprika, cayenne pepper (if using), and black pepper to taste. Pour in the milk and cream, whisking until the ingredients are smooth.

Then add the slightly cooled veggies to the egg mixture and the cheese; if desired, reserve 1 cup of cheese for topping the casserole. 

Step 3 | Assemble Breakfast Casserole and Bake

Pour the egg mixture on top of the casserole dish filled with tater tots, and sprinkle with the reserved cheese. Spray a piece of aluminum foil with oil, cover, and bake in the preheated oven for about 25 to 30 minutes.

Remove the foil and continue baking for 30 to 35 more minutes until the top is bubbly and golden brown and the eggs are set in the middle. 

Allow the casserole to cool for just a few minutes, garnish with basil or parsley then slice and serve for a tasty and easy breakfast!

How to Make Breakfast Casserole Ahead of Time

This casserole may be assembled the night before and baked in the morning or immediately.

If you’re making the casserole ahead of time, there’s no need to preheat the oven. After assembling the tater tot casserole, cover the dish with foil and place it in the refrigerator overnight. Remove the casserole from the fridge, setting it on the counter while the oven preheats.

Next, bake the recipe, covered with foil, for 25-30 minutes. Then, remove the foil and bake for an additional 30-35 minutes until the top is golden brown and the casserole is cooked through. 

More delicious breakfast casseroles

Check out my Biscuit and Gravy Casserole, this sweet and gooey Cinnamon Roll Casserole, Cinnamon French Toast Casserole, and this Hatch Green Chile Relleno Casserole for more delicious ideas the whole family will love!

Variations & Substitutions

I love providing my readers with options! Because life is about options, leave it out if you don’t like something. If you love something, add it and see how it works!

Swap out Veggies in your Tater Tot Bake

Here are a few more great options – roasted red peppers, blanched broccoli florets or broccoli chopped very small, chopped baby spinach, artichoke hearts, and more! Use red onion, shallots or green onions if preferred. You can also try adding par-cooked sweet potatoes, carrots, and peas.

Mediterranean Tater Tot Casserole

Add chopped artichoke hearts and spinach. Then, swap out some of the cheese for crumbled feta cheese or goat cheese, toss in some diced kalamata olives and sun-dried tomatoes. YUM!

Mexican Tater Tot Casserole

Chop and saute a poblano pepper with your other veggies (much like this 10 Vegetable Soup). Add a drained can of mild green chiles, and 1-2 chopped Roma tomatoes. Take it further by browning, draining chorizo, and adding your favorite Mexican cheese to this egg bake! Serve with sour cream, guacamole and salsa.

Non-Vegetarian Breakfast Casserole

If preferred, include meat in the breakfast casserole. Brown and drain your favorite breakfast sausage, turkey sausage, ham, or bacon pieces. Or keep it vegetarian with a meat substitute, like vegan sausage, tofu or vegan bacon.

Storage Tips

Refrigerate For Later

First, allow the casserole to completely cool, then transfer it to an airtight container or cover the dish with plastic wrap. Store in the refrigerator for 3-4 days to enjoy throughout the week as a quick and easy breakfast.

Can you Freeze Leftover Tater Tot Casserole? 

Yes! Keep the casserole for up to three months by storing it in a freezer-safe container or separate it into smaller portions in freezer bags or containers for individual servings. 

Best Way to Reheat your Vegetarian Tater Tot Breakfast Casserole

Reheat refrigerated leftover casserole by placing it in the microwave at 30-second intervals. Cover and return to the preheated 350°F oven for 20-35 minutes until warmed. Warm up a frozen casserole by letting it thaw in the fridge overnight and baking or microwaving it in the morning.

Can I put the tater tots on top of my breakfast casserole?

You can put the tater tots on top of the breakfast casserole to create a crispy layer during baking. Layer them evenly over the top of the vegetarian egg and cheese mixture.

Frequently Asked Questions

Why is my Tater Tot Breakfast Casserole Runny in the Middle?

There could be a few reasons why the middle of your breakfast casserole is runny:

1. Undercooked Eggs: Undercooked eggs are the most common reason for a runny center. Eggs in a casserole need sufficient time to cook and set properly. The center might remain runny if the cooking time or temperature was insufficient.
2. Incorrect Oven Temp: Many ovens run 25° hot/cold; use an oven thermometer to ensure your oven is heating correctly. Follow the recipe’s recommended cooking time and temperature, and consider adjusting it based on your oven’s performance.
3. Too Much Liquid: If your casserole has too much liquid or moisture, it can result in a runny center. This could be due to excessive milk, cream, lower percentages of milk, or other liquids added to the casserole mixture. The excess moisture prevents the eggs from setting correctly. 
4. Pre-Shredded Cheese: Using pre-shredded cheese can impact how your hot dish cooks. 
5. Ingredient Distribution: Uneven distribution of ingredients within the casserole can also lead to a runny center. If the eggs, vegetables, or other ingredients are not evenly spread throughout the casserole dish, it can result in some portions not cooking properly. Ensure the ingredients are mixed thoroughly and evenly distributed in the dish before baking.

To avoid a runny center, follow the recipe instructions closely, ensure proper cooking times and temperatures, and check for ingredient distribution and moisture levels.

You can also tent the casserole with foil and continue baking for a bit longer to help the center cook through without over-browning the top. And sometimes, it’s cooked just perfectly but needs to cool for 10-15 minutes before serving. 

Best Side Dishes to Serve with Tater Tot Casserole

Add these favorite recipes for your weekend brunch.

Best Drinks to Serve with Tater Tot Breakfast Bake

Don’t forget to have a little something to sip on with this flavorful tater tot casserole. Try my incredible Starbucks Copycat Drinks, the Iced Peach Green Tea Lemonade or Passion Tea Lemonade, for a refreshing start to the day.

More Tasty Vegetarian Dishes

• Easy Mexican Street Corn Rice Bowls Recipe
• Crockpot Cracker Barrel Hashbrown Casserole Recipe
• The Best Spanish Rice Recipe (Vegetarian)
• Mexican Chopped Salad with Honey Lime Dressing

More great casserole recipes

• Best Cheesy Hamburger Tater Tot Casserole Recipe
• Easy Tamale Pie Casserole Recipe with Cornmeal Crust
• Best Philly Cheesesteak Casserole Recipe (Low-Carb)
• Breakfast Cinnamon Roll Casserole Recipe (canned rolls)
• Easy Zucchini Ground Beef Casserole

I hope you loved this Easy Tater Tot Breakfast Casserole Recipe— if you did, would you share your creation on Instagram, Facebook, and Pinterest? And be sure to comment below!