Preheat oven to 350 degrees. Line two baking sheets with parchment paper. Set aside.
In a large bowl, whisk together flour, baking powder, baking soda, and spices. Set aside.
In a medium bowl, whisk together eggs and brown sugar until thick and pale. Carefully whisk in oil, vanilla and sweet potato.
Add the sweet potato mixture, all at once, to the flour mixture. Fold together with a spatula until no flour remains. Fold in the cranberries and chopped pecans.
Spoon cookie dough, by the heaping tablespoonful, onto prepared baking sheets two inches apart. Bake for 10 to 12 minutes, or until puffed and lightly golden and a toothpick inserted into the center of one of the cookies comes out clean. Allow to cool for 5 minutes on the baking sheet before removing to a wire rack to cool completely.
Cookies will last, well wrapped, at room temperature for up to 4 days. If storing in layers, separate with parchment or waxed paper so they don't stick together.
Recipe by Stephie Cooks at http://stephiecooks.com/2012/05/14/sweet-potato-cookies/