Corned Beef Hash Casserole
This corned beef hash casserole is layers of crispy tater tots, sautéed peppers and onions, diced corned beef, Swiss cheese, in a savory egg custard. Ready in 90 minutes at 350°F, it feeds 8-10 people and uses leftover corned beef or deli meat. The tater tots get crispy on top and bottom while the egg mixture sets in the middle. It’s perfect for Sunday brunch, holiday breakfasts, or using up leftover St. Patrick’s Day corned beef.
Corned beef hash is one of those “old school recipes” that I don’t see being eaten very much, except at diners. And, my mom’s house.
I was never a big fan of corned beef, but my husband LOVES IT! So does my mom, of course. She usually eats it for breakfast so I thought about adding some eggs and turning it into a casserole.
To make it even easier, I use frozen tater tots. They make crispy layers on the top and bottom which help hold a homemade hash and egg mixture and make it easier to serve.
This is one of those recipes that’s great after a big “food holiday” like St. Patrick’s Day. You might have a bunch of leftover corned beef in the fridge so why not make delicious use of it as a breakfast or dinner with some Irish Soda Bread and cabbage casserole.
You can also make it the star of your holiday party, along with these Irish deviled eggs, these corned beef sliders, and some shamrock rice krispie treats!
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See recipe card for complete information on ingredients and their quantities.
Ingredient Notes
- Tater tots – Frozen tater tots are a life saver because they are delicious and you can use them straight from the freezer. Substitute frozen hashbrowns or the frozen, diced potatoes with bell peppers and onions. Those are delicious! You can even us chopped up frozen french fries.
- Bell peppers – I like to use a mix of red and green for extra color. Green peppers are stronger in flavor while red, yellow, and orange are sweeter. Use what you like!
- Corned beef – Use leftover homemade corned beef or buy it from the deli counter. Canned corned beef hash works in a pinch but this quick homemade version has better flavor and less salt. Substitute the canned hash only in a pinch.
- Whole grain mustard – Yellow mustard is a little more budget friendly and available. Honey mustard is great when you want it a little sweeter.
- Swiss cheese – It melts really well and tastes great with the corned beef. Swap it out for cheddar cheese if you prefer but all the times I tested this recipe the Swiss cheese tasted the best to me with the corned beef.
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How To Make Corned Beef Hash Casserole
- Preheat the oven to 450°F. Spray a 9×13 inch baking dish with nonstick spray. Layer half the frozen tater tots in the bottom, spray them with nonstick spray, and bake for 15 minutes until lightly golden. Remove and reduce oven temperature to 350°F.
- While the tater tots bake, cook diced peppers and onions in a tablespoon of oil over medium heat until softened, about 5 minutes. Add diced corned beef and cook for another 2-3 minutes until heated through. Remove from heat and set aside.
- Sprinkle ¾ cup Swiss cheese over the baked tater tots. Spread the corned beef and vegetable mixture in an even layer over the cheese.
- In a large bowl, whisk together eggs, milk, mustard, and hot sauce in a bowl until well combined. Pour the custard mixture evenly over the corned beef layer.
- Top with the remaining tater tots in an even layer. Sprinkle with the remaining Swiss cheese.
- Bake at 350°F for 50-60 minutes until the egg mixture is set and the top is golden brown. Let it cool for 5-10 minutes before serving so it sets up properly.
For the full recipe and detailed instructions, please refer to the recipe card at the bottom of the post.
Storage & Reheating
Refrigerator: Store any leftovers in an airtight container or leave it in the casserole dish and cover tightly with plastic wrap. It will last for up to 3 days.
Freezer: Cool it completely, wrap tightly with plastic wrap and then foil, and freeze for up to 2 months. The texture changes slightly because of the egg custard when thawed but it still tastes really good.
Reheating from Refrigerator: Warm individual portions in the microwave for 1-2 minutes until heated through. Reheat larger portions in a 350°F oven for 15-20 minutes covered, then uncovered for 5 minutes to crisp up the tater tots again. The air fryer works great too at 375°F for 5-7 minutes for crispy edges.
Reheating from Frozen: Thaw overnight in the refrigerator, then reheat using one of the methods I use above.
Make-Ahead: I love making this the night before! Assemble the entire casserole, cover tightly, and refrigerate overnight. Bake in the morning like normal, adding 10-15 extra minutes since it’s starting cold. You can also take the casserole out of the fridge about 30 minutes ahead of time to take some of the chill off it.
Variations
- Cheddar Version: Use sharp cheddar cheese instead of Swiss for different flavor. The Swiss complements corned beef better but cheddar works fine.
- Add Vegetables: Mix in diced tomatoes, mushrooms, or spinach with the peppers and onions for extra nutrition.
- Spicy Hash: Add diced jalapeños to the vegetable mixture or increase the hot sauce in the egg custard for extra heat.
- Different Potato: Use frozen hash browns, diced potatoes, or even sweet potato tots instead of regular tater tots.
- Sausage Instead: Replace corned beef with cooked breakfast sausage, bacon, or ham for different flavor profiles.
- Mexican Style: Use pepper jack cheese, add black beans and corn, and season with taco seasoning instead of mustard.
- Lighter Version: Use turkey or chicken instead of corned beef and reduce cheese by half for fewer calories.
More Breakfast Casseroles
- Sausage Hashbrown Casserole – Cheesy potatoes with breakfast sausage
- Biscuits and Gravy Casserole – Southern comfort in casserole form
- French Toast Casserole – Sweet cinnamon make-ahead brunch
- Pancake Bacon Casserole – Maple-glazed with crispy bacon
Frequently Asked Questions
Absolutely! This is perfect way to use up leftover corned beef from a pervious dinner or if you have a bunch left after St. Patrick’s Day.
You can but this homemade version tastes better and has less salt. The canned version also contains potatoes which might make it potato overload. Be sure to add in some veggies to balance it out.
A 9×13 inch baking dish is perfect. An 11×7 inch dish works if you halve the recipe. Don’t use anything smaller or it will overflow.
Store leftovers in airtight container in fridge up to 4 days. Reheat in microwave or oven at 350°F until warmed through.
Yes! That’s one of the best things about this recipe. Assemble the whole casserole the night before, cover tightly, and refrigerate for up to 24 hours. Bake in the morning as usual, adding 10-15 extra minutes since it’s starting cold. This is perfect for holiday breakfasts!
Insert a knife in the center and it should come out clean without wet egg clinging to it. The top should be golden brown and the casserole should feel set when you gently shake the dish.
You can but frozen tater tots are easier and crispier. If using fresh potatoes, par-cook them first or they won’t cook through in time.
Cheddar, Gruyere, or Monterey Jack cheeses all work well. I tested this with both Swiss and cheddar and I like Swiss with the corned beef better.
You can add extra and different vegetables. Depending on the vegetables, the casserole can get a little watery. If you want to add extra ones, I would saute them first to remove some of the water.
Recipe Tips & Tricks
- Spray the baking dish with nonstick spray to keep the egg custard and cheese from sticking to the sides of the dish.
- Don’t skip baking the bottom layer of tater tots at high heat. This crisps them before adding moisture from the egg mixture.
- Use a cast iron skillet to cook the vegetables and corned beef. The good sear adds extra flavor.
- Whisk the egg mixture well to break up all the eggs. Lumps of egg white look weird in the baked casserole.
- Pour the egg custard slowly and evenly over the filling. If you pour too fast or in one spot, it can push the meat and vegetables in to the corners of the dish and the middle won’t have any.
- Layer the top tater tots evenly so they all get crispy and golden. Random piles cook unevenly.
- Let it rest for 5-10 minutes after baking. The custard sets up and makes slicing so much easier.
- Reheat in the air fryer for the crispiest edges. The microwave works but makes everything soft.
- This is perfect for using up leftover St. Patrick’s Day corned beef instead of eating the same meal for days.
Use up your leftover corn beef hash, or make it fresh and repurpose it in this corned beef hash casserole recipe. It’s great for St. Patrick’s Day but also a yummy breakfast for house guests!
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Corned Beef Hash Casserole Recipe
Ingredients
- 32 ounces frozen tater tots
- 2 tablespoons olive oil
- 1 medium sweet onion diced
- 1 red bell pepper diced
- 1 green bell pepper diced
- 2 cups cooked corned beef chopped small or shredded
- 8 large eggs
- 1 ½ cups milk
- 2 tablespoons whole grain mustard
- 2 cups Swiss cheese shredded
- dash hot sauce
Instructions
- Preheat oven to 450F.
- Spray a 9×13 pan with nonstick cooking spray.
- Layer ½ the tater tots in the bottom of the dish.
- Spray the top of the tots with nonstick spray.
- Bake until crispy, roughly 15 minutes. Remove and set aside.
- Reduce heat of oven to 350F.
- In a large skillet, heat the olive oil over medium high heat.
- Cook the onion and bell peppers until softened, roughly 5 minutes.
- Add the diced or shredded corned beef and cook another 2-3 minutes.
- Remove from heat and set aside.
- In a medium bowl, combine the eggs, milk, mustard, and hot sauce.
- Whisk to combine and eggs are broken up.Spread ¾ cup Swiss Cheese over the tater tots.
- Spread the corned beef and vegetable mixture and spread into an even layer.
- Pour the egg and milk mixture over the corned beef.
- Add the remaining tater tots over the top.
- Top with the remainder of the Swiss cheese.
- Bake for 50-60 minutes or until the egg mixture is set and a light golden brown.
- Remove and let cool for 5 minutes.
Notes
- Spray the baking dish with nonstick spray to keep the egg custard and cheese from sticking to the sides of the dish.
- Don’t skip baking the bottom layer of tater tots at high heat. This crisps them before adding moisture from the egg mixture.
- Pour the egg custard slowly and evenly over the filling. If you pour too fast or in one spot, it can push the meat and vegetables in to the corners of the dish and the middle won’t have any.
- Layer the top tater tots evenly so they all get crispy and golden. Random piles cook unevenly.
- Let it rest for 5-10 minutes after baking. The custard sets up and makes slicing so much easier.
Nutrition
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