Take the filo dough out to room temperature 2 hours before making the recipe.
Then make the filling. Peel and steam the purple sweet potato. Keep the water that comes out of the sweet potato after steaming. Mash the sweet potato with the granulated sugar.
Cut your filo dough along the long side. You should cut them into equal 2 inch wide and however long your filo dough comes as the length.
Take on sheet of filo, brush a thin layer of oil, stack another sheet, brush with oil. Repeat 4 times, hence there should be 4 sheets each.
To make a spiral: Pipe a thin layer of purple sweet potato mash and wrap the filo around. Then turn the tube to match the picture I have above. This is hard to explain in words, so check out the photos.
To make the triangles: Use the long rectangles from Step 3. Place about 1 tbsp of filling at one end. Fold a corner over and continue to fold tightly to form a triangle. Use oil to seal at the end.
Line a baking sheet with parchment paper. Brush all of the pastries with oil and bake at 400 degrees F for 15 minutes or until golden brown. Be careful of the bottoms as they will brown quickly.