Preheat oven to 325° F.
Line jelly roll pan with parchment paper.
In medium bowl, combine maple syrup, melted butter, salt, vanilla or bourbon, cinnamon, and cayenne (if using).
Whisk until blended.
Add pecans and stir to coat.
Spread pecan mix on parchment paper in single layer.
Bake.
Stir after 10 minutes, and the every 5 minutes after that, until almost no maple syrup remains on parchment paper and nuts are deeply golden, approx. 23-26 minutes.
Remove pan from oven and stir one more time, spreading nuts in even layer across pan.
Let cool for approx. 10 minutes.
While nuts are still warm, separate any large lumps.
Let nuts cool completely on pan.