I agree with Michaels answer regarding a quick steaming or par boil before roasting or frying sweet potato. read more
Roasted wedges or fries of either russets or sweet potatoes give you a lower-fat alternative to their deep-fried relatives. Cut in similarly sized pieces, tossed with oil, salt and pepper and roasted at 425 F, russets take about 40 minutes, while sweet potatoes cook in about 25 minutes. read more
At the same time, the glycemic index of boiled sweet potatoes was found to be about half that of baking or roasting, so boiled sweet potatoes give us less of a blood sugar spike. Make sure to keep the skin on, though. read more