Preparation

• Preheat the oven to 400°F. Lightly butter or grease a 9x13-inch baking dish.
• In a medium pot, melt ¼ cup butter over medium heat. Add diced onions and cook for 3 to 4 minutes until onions turn translucent but not browned. Then add minced garlic and cook for 30 seconds.
• Stir in flour and continue to cook for a minute or two until the flour turns a tan color. Slowly whisk in stock and bring sauce to a slight simmer. The sauce will thicken as it heats. Once the sauce is thick like gravy, stir in the cheddar cheese and season with salt and pepper. Remove from heat.
• In a large bowl add the frozen hash browns and pour the sauce over the hash browns. Stir together well to combine and transfer to the prepared baking dish. Smooth the top.
• Place the casserole in the center rack of your oven and bake for 45 minutes at 400°F. Then turn on the broiler and broil for 5 minutes on high to crisp up the top of the casserole. If your casserole dish is not broiler-safe, then turn the oven up to 500°F and bake for 3 more minutes.
• Let the casserole cool slightly but serve while warm. Leftovers keep in the fridge for 5 days. Reheat in the microwave until warmed through.