In a non-stick skillet over medium heat, toast 1 cup of the finely chopped pecans until light brown. Remove from skillet onto a plate to cool.
In a mixing bowl or stand mixer, combine butter, powdered sugar and brown sugar until combined. Add vanilla extract.
Add gluten free flour, Tara. guar or xanthan gum (leave out if in flour blend), cinnamon and salt until combined.
Add ¾ cup of the toasted pecans. Using your hands, combine the dough until formed into a ball and then roll into a log, about 1 ¾ inch in diameter, about 12 inches long. Make sure to seal any cracks as they won't go away during baking and can cause the cookie to crumble when slicing.
Combine the remaining ¼ cup of toasted pecans and turbinado sugar and spread across a sheet or piece of parchment paper and roll the log in it, coating the entire log.
Wrap the log in parchment paper or plastic wrap and refrigerate for at least 1 hour or until the log is chilled throughout.
Preheat oven to 350 degrees F. Make slices in log about ½ inch thick and place on baking sheet. Baked for 12-14 minutes or until the cookie is golden brown. Allow to cool for 5 minutes on cookie sheet before transferring to a cooling rack. Store cookies in an air-tight container.