Rinse and wash the potatoes, then cut into quarters. If using Yukon Gold potatoes, you do not need to peel them. If using Russet Potatoes, you can peel as much as desired. Add potatoes to the inner pot of your pressure cooker. Cover potatoes with water and add 1/2 tsp salt.
Close lid on pressure cooker and set valve to closed. Cook on HIGH pressure for 8 minutes, followed by a quick pressure release.
Drain potatoes and add the milk, butter, sour cream, garlic powder, black pepper and remaining salt. Mash with a potato masher or potato ricer until desired consistency is reached. Serve hot and enjoy!
If you want to double the recipe, increase cooking time to 10 minutes and test with a fork for tenderness.