Preheat the oven to 250°F (120°C). Line a baking sheet with parchment paper, or a silicone mat.
In a medium bowl, mix the sugar, cinnamon, and salt.
Whisk the egg white and vanilla extract until nice and frothy, about 3-4 minutes. (Make sure the mixture is frothy, as pictured above.)
Add the chopped pecans to the frothed egg white and mix well.
Using a slotted spoon, remove the nuts and toss the pecans with the sugar mixture until the nuts are evenly coated.
Transfer the coated pecans onto a prepared baking sheet and spread them into a single layer.
Bake the pecans, stirring and checking every 15 minutes, until the nuts are evenly browned and crisp, about 45 minutes.
Cool completely before storing. If desired, you can chop the candied pecans into smaller pieces for topping.