Place the potatoes, salt, a few grinds of black pepper, chicken stock, and butter or ghee in the Instant Pot.
Put on the lid and make sure the valve is set to “Sealing”. Press “Manual” and adjust the cooking time to 6 minutes. Cooking will begin automatically and the pot will show the time remaining once high pressure is reached.
When the time is up, push “Keep Warm/Cancel”, carefully turn the valve to “Venting”, and wait for the steam to release.
Remove the lid and use a potato masher to roughly mash the potatoes right in the pot. Add the heavy cream, if using, and continue to mash until your desired smoothness is reached. Taste and add more salt and pepper if desired. Serve hot, topped with additional butter or ghee and minced rosemary or chives.
