To prepare a sweet potato crisp, you'll need: Sweet potatoes, butter, brown sugar, salt, cinnamon, nutmeg, and vanilla. Preheat the oven to 375 degrees F (190 degrees C). Cut the sweet potatoes in half lengthwise and scoop out the insides. Place the cut-side down on the prepared baking sheet. Bake for 20 to 25 minutes, or until the edges are golden brown. Serve warm or at room temperature.