Preheat the oven to 350 degrees F.
Wash the yams and place in a baking dish with the water. Bake until the potatoes are soft and the skins puffy, about 1 1/2 hours. Set aside to cool slightly (leave the oven on).
Peel the yams and place in a medium baking dish. Add the honey, butter, lime juice, salt and pepper. Stir and mash well with a potato masher. Cover with aluminum foil and return to the oven for 15 to 20 minutes, until heated through. Sprinkle the top with sour and serve hot.
Recipe courtesy of Gourmet Magazine