Ingredients
Equipment
Method
- Heat the oven to 350°F and lightly grease a 9-by-13-inch baking dish.
- Melt 2 tablespoons unsalted butter in a saucepan over medium heat. Cook the yellow onion for 5 minutes until soft.
- Stir in all-purpose flour for 1 minute. Whisk in whole milk and simmer 2 to 3 minutes until thickened; remove from heat.
- Stir sour cream, shredded cheddar cheese, kosher salt, and black pepper into the sauce. Fold the sauce into thawed, dry frozen shredded hash browns in a bowl.
- Spread the potatoes in the dish. Melt the remaining 2 tablespoons unsalted butter and toss with plain cornflakes, then scatter over the potatoes.
- Bake 45 to 50 minutes until bubbling at the edges and the topping is golden. Rest 10 minutes before serving.
Notes
Nutrition is an estimate per side serving. Thaw and squeeze the potatoes dry to keep the sauce creamy.
