Boil sweet potatoes. When cooked, drain and mash. Add the rest of the ingredients to the pan and blend well. Preheat oven to 350°F. While oven is heating, grease a 9x13 inch baking dish. Put sweet potato mixture into the baking dish and set aside. In a small dish, combine the topping ingredients until it has the texture of a coarse meal. Sprinkle over the sweet potato mixture. Bake for 30 minutes or until the topping is lightly browned and crisp. Serve as a side dish or even as a dessert.