Wash and peel potatoes and cut into 1-inch pieces. 

Electric Pressure Cooker Instructions: Place potatoes in pressure cooker pot with 3 cups of water and 1 teaspoon salt. Lock lid in place and cook on high pressure for 3 minutes. Naturally release potatoes for 10 minutes and then do a quick release.

Stovetop Instructions: Place potatoes in medium saucepan with 3 cups of water and 1 teaspoon salt. Turn heat to medium high and heat until water starts to boil. Turn down heat to medium, cover the pan and let potatoes for simmer for 15 minutes or until potatoes are easily pierced with a fork.

Drain potatoes well in a colander. As an optional step you can place them back in the hot pan for a few minutes to dry them out, which helps prevent the watery texture (sometimes I skip this step if I'm feeling lazy and I honestly haven't noticed a huge difference).

Mash potatoes as desired. I usually place hot potatoes in a stand mixer with wire whip attachment. Add 1/4 cup butter, sliced into tablespoons and 1/4 cup sour cream. Whip potatoes on low speed until light and creamy. Add a little milk, if desired, to thin (see note) and mix until incorporated. Don't overmix with the mixer or potatoes will become gluey. Taste and add salt and pepper, if needed. 

Serve immediately or transfer to a heat-proof serving dish, cover with aluminum foil and keep in a warm oven until ready to serve. Or you can place the potatoes back in the electric pressure cooker and use the keep warm function until ready to serve. You can stir in a little milk into the mashed potatoes just before serving if they need a little rehydrating after the warming process.