Place 160ml of vegetable stock into the bottom of your Instant Pot and you can measure it out with the cup provided.
Chop up your potatoes so that they cook quicker, you can either have them with or without the skins. Then place them in the bottom of your Instant Pot and make sure they are seasoned with salt and pepper.
Place the lid on your Instant Pot and set the valve to sealing and press manual and take it down to 5 minutes.
Once it has started it will beep and it will beep 6 times when done. Once it has finished allow it to remain on the keep warm function for 10 minutes before removing them.
Remove the Instant Pot and add to it the butter and milk and mash with a potato masher. Finish seasoning it and serve.