Grease a 2-quart rectangular baking dish.
Arrange potatoes evenly in bottom of baking dish.
Sprinkle with cheese, ham, onions.
Combine milk and eggs and seasonings.
Pour over potatoes and cheese.
Cover and refrigerate overnight.
Remove from refrigerator at least 30 minutes prior to baking.
Pre-heat oven to 350°F.
Bake for 40 - 50 minutes until set.
Remove from oven and let rest 5 - 10 minutes.