This recipe couldn't be any easier... All you do is quarter your potatoes (washed and (optionally) peeled) and place them in a steamer so they don't touch the bottom of the pressure cooker. Add some water, and cook for 6 minutes. Comes out awesome every time. Then just add your favorite mashed potato flavorings... butter, garlic, cheese, bacon. It's all good. And mash everything together.
This method allows the steam to reach the potatoes, but keeps the them out of the water in the bottom and prevents them from becoming soggy. We used the basket that came with our pressure cooker, but you could use any metal steamer you have around, as long as it elevates the vegetables above the water line.