Scrub potoatoes and cut them into about 2 x 2 inch pieces. You don't want to cut them too small. If you use red potatoes you will likely just have to cut them in half!
Place the potatoes in a large pot and cover them with water by at least 2 inches. Heat the pot over high heat until the water boils, then turn down the heat to maintain a simmer. Cook the potatoes for about 15 minutes, until they can be very easily pierced with a fork.
Drain the water and begin mashing the potatoes with a masher or a fork. When they are roughly mashed, add in the remainder of the ingredients. Continue to mix and mash the potatoes until they have reached your desired texture. Adjust salt and pepper to taste.