Scrub the potatoes with water to clean them.

Cut the potatoes into 1/2" slices, I cut the potatoes in half then cut slices (you want the potatoes to be roughly the same size so they cook evenly).

Place the potatoes and 1 cup water into the pot of the pressure cooker with 1/2 teaspoon salt.

Set to high temperature for 10 minutes, then do a quick release.

Drain any additional water remaining in the pot.

Add 1/2 cup heavy cream (or whole milk) and the butter and begin mashing by hand with a hand masher or use an electric mixer until you reach the desired smoothness, add additional cream/milk if necessary.

Add additional salt and pepper to taste.