Preheat your oven to 350°F (175°C).
In a large mixing bowl, combine the frozen hash browns, half of the cheese, bell pepper, onion, garlic powder, salt, and pepper.
Spread the hash brown mixture evenly in a greased 9x13 inch baking dish.
In a separate bowl, whisk together the eggs and milk until well combined.
Pour the egg mixture over the hash brown layer in the baking dish, making sure it is spread evenly.
Top with the remaining cheese.
Bake in preheated oven for 45-55 minutes, or until the center is set and the top is golden brown.
Allow the casserole to cool slightly before serving.