Cut ¼ of onions and keep the bulb intact.
Add water in the instant pot.
Place the onions on the trivet and place trivet in the instant pot.
Set the instant pot to “Manual” at high pressure for 5 minutes, release the pressure naturally through steam vent.
Remove the onions carefully.
Place onions bulbs on the grill rack and cook in the oven for 5 minutes.
Take out and enjoy.