Peel and cut the potatoes into 1 inch cubes. In a large pot, cover with cold water and bring to a boil over high heat, covered. Reduce the heat to medium and continue to cook until the potatoes are tender. 30-45 minutes.
Drain and return the pot to the stove, and over low heat, melt the butter. Return the potatoes to the pot and add the rest of the ingredients. Stir well, and mash until smooth.