In a bowl, add the canned soups, milk, garlic powder and pepper; stir to mix well.
In a greased 13x9-inch baking pan, add half the sliced potatoes.
Toss in half the onions, over the potatoes.
Pour half the soup mixture over the potatoes.
Sprinkle half of the cheese over the potatoes.
Place the sliced ham pieces evenly over the potatoes.
Add the remaining sliced potatoes, onions, soup mixture, and cheese.
Cover, and bake in a 375 degree oven for 1 hour.
After 1 hour, uncover the pan, and continue baking for 30 minutes more.
Note: Sometimes I'll use ham steaks that come in a 16-oz pkg., which I cut them into 3/4 to 1-inch pieces. (I used John Morrell Ham Steaks, and I used the entire pkg.). Also, I think one could add a bit more garlic powder & white pepper (possibly an 1/8 teaspoon more of each).