Step 1

Place sous vide in a large container on water and preheat to 194° Fahrenheit (90° Celsius).

Step 2

Peel skin from potatoes then cut into ½-inch slices.

Step 3

Place all ingredients into a zip-top bag then remove air from the bag. Place bag in sous vide bath and cook for 1 hour.

Step 4

Remove bag from bath, then transfer the just cooked potatoes to a large bowl and mash until pretty smooth. Reserve the milk and butter liquid for the next step.

Step 5

Stir in half of the liquid from inside the bag into the potatoes before tasting and adjusting any seasoning as desired.