Peel and slice the potatoes into rounds and place in the Instant Pot.
3 lb. Russet potatoes, peeled and sliced (about 8-9 small potatoes or 5-6 medium potatoes)*
Add in the garlic and salt. Cover potatoes with ~6 cups of water or enough for the potatoes to be completely covered.
2 tsp. crushed garlic (about 4 cloves), 2 tsp. salt, divided, 6 cups water (enough to cover potatoes)
Secure the lid, set the valve to seal and cook on manual HIGH pressure for 15 minutes. (Note: Instant pot will take a few minutes to reach pressure, then time will begin to count down).
When the timer goes off, quick release the pressure using a dish towel or pot holder.
Reserve 1/2 cup of the starchy water (see notes). Drain the potatoes and then return back to the pot.
Add in the butter and stir. Then add in remaining ingredients: remaining salt, 1/4 cup of reserved starchy water, Parmesan cheese, milk, sour cream, garlic powder and pepper. Mash until smooth.(Do not over work the potatoes, see notes).
8 Tbsp. butter, unsalted (1 stick or 1/2 cup), 1/2 cup Parmesan cheese, grated, fresh, 1/2 cup reserved starchy water from potatoes*, 1/4 cup whole milk, 1/4 cup sour cream, 1/2 tsp. garlic powder, 1/2 tsp. pepper
Serve with chives and more butter on top if desired.
1 Tbsp. chives/herbs of choice (fresh preferred)