Pre-heat the oven to 350°. Place the pecans on a baking sheet and toast them in the oven for 10 to 15 minutes until their color has deepened. Stir half way through the baking time to ensure they are toasted evenly. Remove from oven and cool completely.

Place the pecans in a food processor fitted with the metal blade and pulse until they are finely ground to the consistency of corn meal. Do not over process them or you will have nut butter.

Add the butter, and powdered sugar. Pulse the processor a few times then add the flour vanilla and salt. Run the food processor until the dough comes together in a clump. 

Wrap the dough in plastic wrap and refrigerate for 6 hours.

Pre-heat the oven to 375°. Grease two baking sheets or line them with parchment paper. Combine the 2 ½ cups of powdered sugar with the cinnamon in a large bowl or pie plate and set aside.

Roll level teaspoons of dough into small balls and place them about an inch apart on the baking sheets. Bake 12 to 15 minutes until a pale golden color. Transfer the hot cookies directly to the powdered sugar mixture and roll them to cover completely with the sugar. Set aside to cool completely (the powdered sugar will melt into the hot cookies and look goopy). After completely cooled, roll the cookies once more in the powdered sugar.