Ingredients:

  • Frozen Shredded Hash Browns, 32 oz bag (900 g), thawed and drained
  • Unsalted Butter, 4 Tbsp (55 g), for the roux
  • All-Purpose Flour, 1/4 cup (30 g)
  • Whole Milk, 2 cups (480 ml), warmed slightly
  • Full-Fat Sour Cream, 1 cup (240 g)
  • Mature (Sharp) Cheddar Cheese, grated, 2 cups (220 g) total
  • Onion Powder, 1 tsp (5 ml)
  • Garlic Powder, 1/2 tsp (2.5 ml)
  • Dried Mustard Powder, 1/2 tsp (2.5 ml)
  • Kosher Salt, 1 tsp (5 ml)
  • Freshly Ground Black Pepper, 1/2 tsp (2.5 ml)
  • Cornflakes (or Panko breadcrumbs), 1 1/2 cups (75 g), roughly crushed
  • Unsalted Butter, 2 Tbsp (30 g), melted, for topping

Instructions:

  1. Preheat oven to 350°F (175°C). Grease the 9x13 inch casserole dish thoroughly.
  2. Place the thawed hash browns in a clean kitchen towel or several layers of paper towels and squeeze firmly to remove excess moisture. Set aside in a large mixing bowl.
  3. Start the Roux: In the large saucepan, melt 4 Tbsp (55g) of butter over medium heat. Add the flour and whisk continuously for 1–2 minutes until a smooth paste (roux) forms and smells slightly nutty.
  4. Add Milk: Gradually pour in the warm milk, whisking constantly to prevent lumps. Bring the mixture to a simmer, stirring until the sauce thickens significantly and coats the back of a spoon (about 5–7 minutes). Remove from heat.
  5. Finish Sauce: Stir in the onion powder, garlic powder, mustard powder, salt, and pepper. Fold in the sour cream and 1.5 cups (165g) of the grated cheddar until fully melted and smooth. Taste and adjust seasoning as necessary.
  6. Combine Ingredients: Pour the entire cheese sauce mixture over the prepared, drained hash browns. Fold gently with a spatula until the potatoes are evenly coated. Scrape the mixture into the prepared casserole dish.
  7. Prepare Topping: In a small bowl, combine the crushed cornflakes and 2 Tbsp (30g) of melted butter. Mix well.
  8. Layer Topping: Sprinkle the remaining 1/2 cup (55g) of cheese evenly over the potatoes, then distribute the buttered cornflakes over the cheese layer.
  9. Bake: Place the casserole dish in the preheated oven. Bake for 40 minutes, covered loosely with foil (this prevents the topping from burning).
  10. Brown: Remove the foil and continue baking for 10–15 minutes, or until the potatoes are bubbling throughout and the topping is golden brown and crisp.
  11. Rest: Remove from the oven and let the casserole rest for 10–15 minutes before serving. This allows the sauce to set properly.