Preheat your oven to 375 degrees Fahrenheit, and spray a 3-quart baking dish with cooking spray.
In a large bowl, mix the evaporated milk, flour, paprika, seasoning salt, nutmeg, and cayenne until thoroughly combined.
Layer the thinly sliced potatoes evenly in the baking dish, and pour the milk mixture over the top, covering all the layers.
Cover the baking dish with foil, and bake for 60 minutes in the preheated oven.
Remove the foil, and continue baking for an additional 15 to 20 minutes, until golden and bubbly.