Preheat the oven to 350ºF. Add the brown sugar, granulated sugar, cinnamon, and salt to a bowl, then stir them together until evenly combined.
Separate the egg and place the egg white in a large bowl. Lightly whisk the egg white until it is frothy, then add the vanilla extract and briefly whisk again to combine.
Add the pecans to the egg white mixture and stir to coat. Sprinkle the cinnamon sugar mixture over the nuts and stir to coat again.
Spread the coated nuts out onto a large baking sheet lined with parchment paper.
Bake the nuts in the preheated 350ºF for 25 minutes, stirring once halfway through.
Allow the nuts to cool completely before enjoying or storing for later.