01 -
Preheat the oven to 175°C. Lightly grease a 23×33 cm baking dish with butter and set aside.
02 -
In a small bowl, mix the grated sharp cheddar and Monterey Jack cheeses. Set aside.
03 -
Place the defrosted hash browns in a large bowl. Toss with 4 tablespoons melted butter, ½ teaspoon salt, and ½ teaspoon pepper. Stir in sour cream and 2 cups of the cheese mixture. Set aside.
04 -
Melt 4 tablespoons of butter in a large skillet over medium heat. Sauté diced onion for 4 to 5 minutes until translucent. Add minced garlic and cook for 1 minute, stirring frequently. Sprinkle flour over the mixture, stirring constantly for 1 minute. Gradually whisk in chicken broth and milk. Simmer for 3 to 4 minutes until thickened. Season with remaining salt and pepper. Remove from heat.
05 -
Pour the creamy sauce over the potato mixture and fold gently to combine. Transfer to the prepared baking dish.
06 -
Sprinkle the remaining cheese evenly over the potatoes. In a bowl, combine melted butter with crushed cornflakes, tossing to coat. Evenly spread the cornflake topping over the cheese layer.
07 -
Cover the dish with foil and bake for 20 minutes. Remove foil and continue baking for an additional 15 to 20 minutes until edges are bubbling and topping is golden brown.
08 -
Allow the casserole to rest for 10 minutes before serving.