Quick Corned Beef Hash Breakfast Casserole

I’ve always had a soft spot for corned beef hash. Something about that mix of crispy potatoes and savory meat just hits the spot, especially first thing in the morning. But standing at the stove, flipping and stirring until everything’s just right? Not exactly what I want to do when I’m still half asleep.

That’s where this breakfast casserole comes in handy. It takes all the good stuff from traditional corned beef hash and turns it into something you can prep the night before. I usually get everything ready while I’m cleaning up after dinner, pop it in the fridge, and then just slide it into the oven when I wake up. By the time everyone’s out of bed, breakfast is ready to go.

Whether you’re planning a weekend brunch or just want to make your morning routine easier, this casserole has you covered. It’s got all those classic hash house flavors, but without the fuss of standing over the stove. Plus, leftovers reheat beautifully for breakfast all week long.

What Kind of Hashbrowns Should I Use?

For this breakfast casserole, you’ll want to stick with frozen hashbrown cubes (sometimes called diced hashbrowns) rather than the shredded variety. The cubed style holds up better in a casserole and gives you nice, substantial potato bites throughout the dish. Most grocery stores carry these in the frozen section – look for ones that are plain, without added seasonings or sauces. If you can only find shredded hashbrowns, they’ll work in a pinch, but the texture of your casserole will be a bit different. Just make sure your hashbrowns are fully thawed and patted dry before using them to remove any excess moisture that could make your casserole watery.

Options for Substitutions

This breakfast casserole is pretty adaptable and here’s how you can switch things up:

• Frozen hashbrown cubes: You can use fresh potatoes (peeled and diced) instead of frozen – just par-boil them for 5 minutes first. Or try frozen shredded hashbrowns, but reduce the amount to 6 cups since they pack more densely.
• Bell peppers: Any color bell pepper works here! You can also swap them with diced mushrooms, zucchini, or even frozen mixed vegetables if you’re in a pinch.
• Corned beef: While corned beef gives this dish its signature flavor, you could use regular diced ham, crumbled breakfast sausage, or even bacon if needed. For a vegetarian version, try using a meat substitute or extra vegetables.
• Whole milk: Feel free to use 2% milk or even half-and-half. For a richer taste, try using part heavy cream with your milk.
• Cheddar cheese: Swiss cheese works great with corned beef, or try a mix of cheddar and monterey jack. Just avoid soft cheeses as they might make the casserole too wet.
• Powdered mustard: If you don’t have powdered mustard, use 2 teaspoons of prepared Dijon mustard instead.

Watch Out for These Mistakes While Cooking

The biggest challenge when making a corned beef hash breakfast casserole is ending up with soggy hash browns – to prevent this, make sure to thaw and pat them completely dry before cooking, and pre-cook them in the oil until they’re golden brown and crispy.

Another common mistake is overcrowding the pan when sautéing the vegetables, which leads to steaming instead of browning – work in batches if needed and give your peppers and onions plenty of space to develop a nice caramelized edge.

Temperature control is crucial: baking at too high a heat can result in overcooked eggs and burnt edges while the center stays raw, so stick to 350°F and check the middle with a knife before removing from the oven.

For the best cheese pull and texture, avoid using pre-shredded cheese which contains anti-caking agents – instead, grate your own cheddar, and don’t add all the cheese at once; reserve some to sprinkle on top during the last 10 minutes of baking.

What to Serve With Corned Beef Hash Casserole?

This hearty breakfast casserole is practically a complete meal on its own, but there are some tasty sides that can make it even better! A simple fruit salad with berries and citrus provides a fresh contrast to the rich, savory flavors of the casserole. I like to serve it with some toasted sourdough or rye bread on the side – these breads have just the right tang to complement the corned beef. For a traditional diner-style breakfast experience, add a dollop of sour cream, some fresh chives, or hot sauce on top, and don’t forget a pot of strong coffee to wash it all down.

Storage Instructions

Keep Fresh: This hearty breakfast casserole will stay good in the fridge for up to 4 days when stored in an airtight container. It’s actually one of those dishes that tastes even better the next day, as the flavors have time to meld together!

Freeze: You can freeze this casserole either before or after baking. If freezing unbaked, assemble everything but hold off on the last cheese topping – add that when you’re ready to bake. Wrap it well in plastic wrap and foil, and it’ll keep in the freezer for up to 3 months. Already baked portions can be frozen in airtight containers for up to 2 months.

Reheat: To reheat individual portions, pop them in the microwave for 1-2 minutes, or until heated through. For a crispier top, you can use the oven at 350°F for about 15-20 minutes. If reheating from frozen, thaw overnight in the fridge first for best results.

Preparation Time	15-20 minutes
Cooking Time	90-95 minutes
Total Time	105-115 minutes
Level of Difficulty	Medium

Estimated Nutrition

Estimated nutrition for the whole recipe (without optional ingredients):

• Calories: 3000-3500
• Protein: 180-200 g
• Fat: 210-240 g
• Carbohydrates: 150-170 g

Ingredients

For the hashbrown base:

• 4 cups frozen hashbrown cubes
• 2 tbsp cooking oil (neutral oil like canola or vegetable)

For the filling:

• 1 red bell pepper (diced into 1/2-inch pieces)
• 1 green bell pepper (diced into 1/2-inch pieces)
• 1 lb corned beef (cut into 1/2-inch squares)
• 1 medium yellow onion (finely diced)
• 1/2 cup cheddar cheese
• 1 tbsp cooking oil

For the custard:

• 1 1/2 cups whole milk (I use Horizon Organic whole milk)
• 1 tsp powdered mustard (helps to emulsify the custard)
• 8 large eggs

For the topping:

• 1 cup cheddar cheese
• 1 1/2 cups cheddar cheese (freshly shredded for best melt)
• 3 cups frozen hashbrown cubes

Step 1: Prepare and Bake the Hashbrowns

Preheat your oven to 450°F.

Grease a 9×13-inch baking dish with non-stick spray.

Spread 4 cups of frozen hashbrowns evenly across the bottom of the prepared baking dish, then drizzle them with 2 tablespoons of oil.

Bake in the preheated oven for 30 minutes.

Allow the hashbrowns to cool slightly for about 15 minutes once they are done baking.

Step 2: Sauté the Vegetables and Corned Beef

While the hashbrowns are cooling, heat the remaining 1 tablespoon of oil in a large skillet over medium-high heat.

Add the onions, red, and green peppers to the skillet, stirring periodically until they begin to soften.

Add in the corned beef and continue cooking for a couple of minutes until everything is well combined and heated through.

Step 3: Prepare the Egg Mixture

In a large bowl, whisk together 8 eggs, 1 ½ cups of whole milk, and 1 teaspoon of dry mustard until the mixture is smooth and well combined.

This will become the custard that holds your casserole together.

Step 4: Assemble the Casserole

Sprinkle 1/2 cup of cheese over the baked hashbrowns in the casserole dish.

Evenly distribute the cooked vegetables and corned beef over the cheese layer.

Pour the egg mixture over the top, ensuring even coverage.

Sprinkle 1 ½ cups of additional cheese over the egg layer, and then add the remaining 3 cups of frozen hashbrowns on top.

Step 5: Bake the Casserole

Cover the dish with foil and bake in the preheated oven for 30 minutes.

After 30 minutes, remove the foil and continue baking uncovered for an additional 30 minutes to allow the top to crisp up.

Step 6: Broil and Finish

Change your oven setting to broil, keeping the grill placement as is.

Sprinkle the last cup of cheese over the top of the casserole.

Place the dish back in the oven, uncovered, for about 5 minutes, or until the hashbrowns turn golden and the cheese is fully melted.

Once done, remove the casserole from the oven and let it sit for about 15 minutes before serving.

Enjoy your delicious homemade hashbrown casserole!