Put the sweet and white potatoes into a pan of cold salted water, bring to the boil, then simmer for 10-
Form the mixture into 6 cakes. Tip the remaining 3 tbsp polenta onto a plate and roll the cakes in it to coat. The mix will be quite wet at this stage, but the extra polenta will help to keep them together during cooking. Cover and chill for 15 min.
Heat the oil in a large sauté pan over a medium heat. Add the cakes and fry for 3-
* sweet potato is listed as moderate on the polyol list. If new to the diet we recommend that you simply remove it and use normal potato.