Combine potatoes, garlic, and broth in Instant Pot®. Season with salt and black pepper, to taste, and stir to combine. Add lid and lock into place. Switch the vent to “Sealing” and set the “Manual” setting to 8 minutes.
When cook time is complete, allow pressure to release naturally for 10 minutes, then manually release any remaining pressure.
Carefully remove the lid and add heavy cream and butter. Mash the potatoes with a potato masher or immersion blender until almost smooth, but still slightly chunky. Taste and season with additional salt and black pepper, if desired.
Transfer to a serving bowl and serve immediately. Enjoy!