Step 1: First, lightly grease the pan with non-stick spray. In a medium bowl add the hash browns (defrosted from frozen or freshly grated), soup, sour cream, diced onions, garlic powder, diced ham (if using) and half of the shredded cheese.
Step 2: Next, pour one cup of water into the pressure cooker, and use your silicone or aluminum foil sling to lower the pan into the Instant Pot. Cook on HIGH pressure for 35 minutes.
Step 3: Whether you brown the mock scalloped potatoes with ham (or without), let the casserole sit and cool for at least 10 minutes before serving. This will help the dish to stay firm and not spread out so much when plated.