Preheat oven to 400 degrees and grease 9" x 9" pan.
In a medium bowl whisk milk into the flour. Set aside.
Lay ⅓ of the potatoes into a single layer on the bottom of the pan, shingling them (it's ok if they overlap a little).
Top the potatoes with ½ teaspoon salt, ¼ teaspoon pepper, ¼ teaspoon onion powder, ⅔ cup ham, and ½ cup cheese.
Next, shingle ⅓ of the potatoes into the pan.
Top the second layer of potatoes with ½ teaspoon salt, ¼ teaspoon pepper, ¼ teaspoon onion powder, ⅔ cup ham, and ½ cup cheese.
Shingle the remaining ⅓ of the potatoes into the pan.
Top the third layer of potatoes with remaining ½ teaspoon salt, ¼ teaspoon pepper, ¼ teaspoon onion powder, and ⅔ cup ham.
Pour milk evenly over the potatoes. Top with remaining ½ cup cheese and cover.
Bake covered for 30 minutes.
Remove cover and bake uncovered for an additional 30 minutes. Serve immediately.
