1. Preheat oven to 350 degrees.
2. Place the yams in a baking dish with the water and bake until they are soft and skins are puffy, about 1 1/2 hours. Set aside to cool.
3. Peel the sweet potatoes and place in a mediuim baking dish. Add honey, butter, lime, salt and pepper and mash together.
4. Cover with foil and bake 15-20 minutes, until heated through.
5. Serve hot, garnished with sour cream or creme fraiche.