Maker sure your liner is in your Instant Pot! Pour 2 cups warm water into the inner liner, and place trivet inside. Place cake pan on top of trivet, Close and lock lid, and set nozzle to sealing position. Press Pressure cook button, and adjust time for 45 minutes.
Once done, Quick Release all pressure. Once pressure has been released, remove lid at an angle and allow to cool for a few minutes. Lift trivet by handles. If your trivet doesn't have handles, allow to cool for 5 minutes, and carefully life with kitchen gloves.
Remove foil, and sprinkle top with cheese. Place under broiler or in a toaster oven to melt cheese and to slightly brown the top.