Step 1

Preheat the oven to 400 degrees F. Spray a 9x13-inch baking dish with cooking spray.

Step 2

Dump the frozen hashbrowns into the baking dish. Drizzle with the melted butter and season with 1/2 teaspoon of the salt and 1/4 teaspoon of the pepper. Toss, then spread in an even layer.

Step 3

Bake for 25 to 30 minutes until the hashbrowns are lightly browned on top and softened. While the hashbrowns are baking, combine the eggs, evaporated milk, seasoned salt, remaining 1/2 teaspoon kosher salt, remaining 1/2 teaspoon pepper, onion powder, and smoked paprika in a large bowl. Beat well and set aside.

Step 4

Remove the hashbrowns from the oven and reduce the oven temperature to 350 degrees F or turn it off if using the overnight approach.

Step 5

Sprinkle the ham and shredded cheese over the potatoes, tossing a bit to combine. Pour the seasoned egg mixture evenly over the potatoes, making sure to get some around the edges of the pan. At this point, the casserole can be baked immediately or refrigerated overnight and baked in the morning.

Step 6

Make sure to preheat the oven to 350 degrees F if using the overnight approach. Bake for 40-45 minutes until the edges start to brown slightly and the center is just set and doesn't jiggle. Check on the casserole at the 25-30 minute point to see if it is browning too much and cover with foil, if needed.

Step 7

Garnish with the chopped green onions, then cut into large squares and serve hot.