Can I make hash brown casserole without thawing the potatoes first?

It is not recommended. Frozen shreds release close to a cup of water as they bake, which thins the sauce and leaves the center soupy. Thaw overnight in the fridge or for two hours on the counter, then squeeze them dry in a clean towel.

Why did my hash brown casserole turn out watery?

Almost always, the potatoes went in wet, or the sauce was pulled before it thickened. The sauce should coat the back of a spoon before it meets the potatoes, and the shreds should be squeezed until no more water drips out.

Can I use cubed hash browns instead of shredded?

Yes, with a texture change. Cubes stay firm and distinct, so the casserole eats more like a potato bake than a soft, scoopable side. Add about 10 minutes to the bake and check that the center cubes are fully tender.

How do I keep the cornflake topping from going soggy?

Add it near the end, never at the start. Toss the flakes with melted butter and scatter them over the casserole for only the last 12 to 15 minutes of baking, so they toast in dry heat instead of steaming.

Can I freeze hash brown casserole before baking?

Yes. Assemble it without the topping, wrap the dish tightly and freeze for up to 2 months. Thaw overnight in the fridge, add 10 minutes to the bake, and finish with fresh buttered cornflakes at the end.

Hash Brown Casserole: Cheesy, From Scratch, No Soup

Ingredients

Scale

1 bag (30 ounces, 850 g) frozen shredded hash brown potatoes, thawed
4 tablespoons (57 g) unsalted butter, plus more for the dish
1 cup (150 g) finely diced yellow onion
2 cloves garlic, minced
1/4 cup (31 g) all-purpose flour
1 cup (240 g) whole milk
1 cup (240 g) low sodium chicken broth
1 teaspoon (6 g) fine sea salt
1/2 teaspoon (1 g) black pepper
1/2 teaspoon (1 g) dry mustard powder
1 cup (240 g) sour cream, at room temperature
2 1/2 cups (283 g) shredded sharp cheddar, divided
2 cups (60 g) cornflakes, lightly crushed
2 tablespoons (28 g) unsalted butter, melted

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Instructions

Heat the oven to 350°F. Butter a 9 by 13 inch baking dish and set it aside.
Squeeze the thawed hash browns in a clean kitchen towel, a handful at a time, until no more water drips out. Set them in a large mixing bowl.
Melt the 4 tablespoons (57 g) of butter in a medium saucepan over medium heat. Add the onion and cook for 4 to 5 minutes, until soft and sweet.
Stir in the garlic and cook for 30 seconds. Sprinkle the flour over the onions and cook, stirring, for 1 full minute.
Slowly whisk in the milk, then the broth. Simmer for 2 to 3 minutes, whisking, until the sauce thickens enough to coat the back of a spoon.
Take the pan off the heat. Stir in the salt, pepper and mustard powder, then the sour cream, until smooth.
Fold 2 cups (226 g) of the cheddar into the warm sauce until mostly melted. Pour the sauce over the potatoes and fold until every shred is coated.
Scrape the mixture into the prepared dish and smooth the top. Scatter the remaining 1/2 cup (57 g) of cheddar over it.
Bake uncovered for 35 minutes, until the edges are bubbling. Toss the crushed cornflakes with the 2 tablespoons (28 g) of melted butter and scatter them over the top.
Bake for 12 to 15 minutes more, until the topping is deep golden and the center is hot and set. Rest for 10 minutes before serving.

Notes

Squeeze the thawed potatoes very dry; their water is the main cause of watery casseroles. The dish can be assembled, without the cornflake topping, up to 24 hours ahead and refrigerated; add 10 minutes to the bake when it goes in cold.

Prep Time: 20 minutes
Cook Time: 50 minutes

Nutrition

Calories: 290
Sodium: 410
Saturated Fat: 11
Protein: 9
Cholesterol: 51