Rough chop your potatoes and cauliflower and add them to the Instant Pot with 1 cup of water. Set for 15 minutes then release steam. (Alternative: boil until soft in a pot on the stove)
In a large bowl mash the cauliflower and potatoes together with the spices & milk. Mash to your desired consistency.
Serve warm with steamed greens and top with mushroom gravy, see below!