*Depending on the strength and reliability of your toaster, you may want to opt for roasting in the oven. It takes a little longer but yields the most consistent toast/roast! If you opt for this method, preheat the oven to 375F and line a baking tray with parchment paper. Spread the sweet potato slices into a single layer in the pan and bake for 20 to 25 minutes, or until tender.