Add all of the ingredients to the Instant Pot, give them a good mix to distribute the seasonings.
Cover with the lid, and press on MANUAL or PRESSURE COOK (this depends on what model of Instant Pot you have), and set on 5 minutes.
Allow the Instant Pot to come to pressure, and cook for 5 minutes. When it's done, quickly release the steam and carefully open the lid. Give it a quick stir, and serve warm.
Notes
If you're not a fan of mushrooms, omit them. You could also use cubed butternut squash or pumpkin, and add a couple of whole garlic cloves.
Keep in mind that we want the potatoes to have a very soft texture, and it starts breaking down. However, if you prefer your veggies a bit firmer then reduce the cooking time by 1-2 minutes.