Whisk together sugar, flour, baking powder, cinnamon, and salt in a large bowl. Add cubed butter or coconut oil to the bowl, and cut the mixture together until the mixture resembles bread crumbs. Or, you can pulse the mixture in a food processor.
Add the sweet potato and egg to the mixture. Mix well. Pulse in a food processor (if using one) until the dough comes together.
Mold the dough into a 6-7″ cylinder. Wrap tightly with seran wrap and refrigerate for at least an hour. (I actually didn’t have saran – the joys of moving – and wrapped it in a zip-loc bag) or place in the freezer for about 30 minutes.
Once chilled, cut the dough into 1/4″ round pieces. I found the easiest way to do this was to use waxed floss. Cut an 8-12 inch piece, slide it under the log of dough about a quarter inch, and cross at the top. Pull through, and repeat.
Dip Each piece in granulated sugar on both sidea, and place on an ungreased cookie sheet.
Bake in batches for about 12 minutes – until the bottom of the cookies are golden brown.
Cool the cookies completely on a cooling rack.
P.S. They’re great any time any way, but these gluten free sweet potato cookies are divine while they’re hot!