Thinly slice the potatoes and cut the ham into small squares.
In a medium bowl whisk together the heavy cream, milk, garlic, flour, salt, black pepper and cilantro.
Spray a round pan that fits inside your Instant Pot (I used 8" round with 2" high sides) with cooking spray.
Layer half of the potatoes and ham in the prepared pan, followed by half of the cheese.
Pour half of the liquid over the top. Repeat with the rest of the potatoes, ham and liquid, reserving the remaining cheese for later.
Place a trivet on the bottom of your inset pan of your Instant Pot and pour 1-2 cups of water
Carefully lower your pan down into the liner of your pressure cooker.
Close the lid and make sure the pressure release valve is set to sealing. Set Instant Pot to Manual on High pressure for 25 minutes. Then do a Quick Release, but carefully turning the valve to venting.
Carefully pull the pan out by the trivet handles and place pan on a baking sheet.
Top with the remaining cheese and place under the broiler in your oven for 3 minutes. (Or if you don't want to turn on your oven you can just leave the potatoes in the pressure cooker, top with cheese and cover for 5 minutes before removing from liner).
Rest the potatoes for about 10-15 minutes before serving, so the sauce thickens and gets absorbed into the potatoes. Enjoy!