Prepare Butter and Potatoes: Bring unsalted butter to room temperature by placing it on counter 2 hours before cooking. After peeling and washing the potatoes, cut them into quarters.

Pressure Cook Potatoes: Place 1 cup (250ml) cold water and a steamer rack in Instant Pot. Put quartered potatoes on the steamer rack. Close the lid, then turn Venting Knob to Sealing Position.Pressure cook at High Pressure for 8 minutes, then Quick Release.

Heat Milk & Cut Butter: Once Instant Pot gets up to pressure, heat milk over medium-low heat on the stove. When the milk reaches a simmer, turn off the heat. Cut room temperature unsalted butter into cubes.

Mash Potatoes: Open the lid carefully. Let the Instant Pot stay in Keep Warm Mode. Transfer potatoes to a large bowl. Discard the water and remove the steamer rack from inner pot. Rinse and dry the inner pot really well with a towel. Place inner pot back in the Instant Pot. Potato Masher Instructions: Transfer the potatoes back into the inner pot, then mash the potatoes.Food Mill Instructions: Layer the food mill on the inner pot, then mash the potatoes into the inner pot.Give the mashed potatoes a few quick stirs with a silicone spatula.

Melt Butter & Add Milk: Switch Instant Pot to Slow Cook Less Mode. Add half of the room temperature unsalted butter and melt it into the potatoes by stirring gently with a silicone spatula. Add in remaining unsalted butter, then repeat this step.Change Instant Pot to Keep Warm Mode.Pour hot milk on the mashed potatoes, then gently stir it in. Allow the potatoes to absorb the milk. Season with kosher salt and taste to adjust until desired saltiness. For reference, we used approx. 4 pinches of coarse kosher salt.

Serve: Serve these Michelin-star inspired mashed potatoes immediately as a side dish. Enjoy!