Wash, peel, and chop potatoes.
Put the potatoes in the instant pot and add 1 cup of water.
Put the lid on, seal the steam valve, and cook on manual/high pressure for 12 minutes.
When the cooking cycle is complete, do a quick pressure release by twisting the steam valve to “venting”.
Open the lid. There won’t be much water, so you don’t need to drain. Add butter, salt, milk, and pepper to taste.
Mash until combined and creamy- but don’t overwork or the potatoes will become very gluey.