Preheat the oven to 350°F. Grease a 9-x-13-inch baking dish.
In a large bowl, mix eggs, milk, hash browns, sausage, salt, pepper, and 1 cup of cheese until combined. Pour into the prepared baking dish.
Bake for 32–35 minutes. Remove from the oven and add the remaining ½ cup cheese over the top. Place back in the oven and bake for an additional 3–5 minutes.
Make Ahead. Make this breakfast potato casserole through Step 2 up to 24 hours in advance. Just cover and keep in the refrigerator until ready to bake. Uncover and bake; you may need to add a few additional minutes to the baking time. Variations:
Mexican: Add chopped bell peppers and use Mexican blend cheese instead of cheddar.
Meat Lovers’: Add cooked bacon along with the sausage.
Low-Fat: Omit the meat and add a cup of chopped spinach and other vegetables.