Fill a large pot with water, and heat over high until boiling.
While the water is coming to a boil, chop the potatoes into 1″ cubes. I like to leave the skins on, but feel free to peel the potatoes if you prefer no skins.
When the water is boiling, add the potatoes to the water and continue to boil for 15-20 minutes, until the potatoes are tender and a fork is easily inserted and removed from the potato.
Drain the potatoes in a colander, then return the potatoes back to the pot. Turn off the heat. Add 1.5 cups chicken stock, and start mashing with a potato masher. You want the potatoes to become smooth and velvety. Continue adding chicken stock until the potatoes are smooth with no lumps. It usually takes me the whole 2 cups chicken stock, but it will depend on your potatoes.