You make mashed sweet potatoes by boiling peeled and cubed sweet potatoes in salted water for fifteen to twenty minutes until fork tender. Drain the cooked potato chunks thoroughly in a colander before returning them to the warm pot. Mash the potatoes with butter, warm milk, a pinch of salt, and a dash of cinnamon until smooth and creamy. Serve this delicious side dish warm alongside your favorite roasted meats or holiday meals.