Remove, and set oven temperature to 375ºF. Once cool enough to handle, remove skin from sweet potato and mash with a fork in a bowl with dry ingredients. Combine beaten egg, warmed butter, molasses, and vanilla in separate bowl. Then combine all ingredients in a food-grade plastic bag, using your hands to thoroughly mix the ingredients with a gentle kneading motion, and place in the refrigerator to cool for at least 1 hour. Place parchment paper on a baking sheet. Dough will be gooey in consistency. Flour hands and form the dough into 3-inch cookies. Bake for 40 minutes, or until tops are browned.