Heat the oven to 350°F (175°C). Toast the pecans for 6 to 8 minutes, then cool and chop them.
Beat the soft butter, powdered sugar, vanilla and salt on low until combined. Then beat on medium for 3 minutes, until fluffy.
Whisk the flour and cinnamon together in a medium bowl.
Add the flour mixture to the butter and mix on low until almost combined. Scrape the bowl, add the pecans, and mix until the dough comes together.
Shape the dough into a log about 2 inches wide and 7 inches long. Wrap it in parchment paper.
Chill the log for at least 2 hours, or up to 3 days.
Heat the oven to 350°F (175°C). Line two baking sheets with parchment paper. Slice the log into rounds about 1/2 inch thick and place them 1 inch apart.
Bake for 10 minutes. Swap and turn the sheets, then bake another 10 minutes, until golden brown.
Cool on the sheet for 5 minutes, then move to a wire rack to cool completely.