Line a bake sheet with parchment paper and preheat oven to 300˚F.
In a small bowl, mix brown sugar, granulated sugar, and cinnamon.
In a medium bowl, whisk egg white and vanilla until frothy.
Add pecans to egg white and toss to coat.
Add sugar mixture to pecans and stir to coat evenly.
Spread pecans evenly on parchment lined bake sheet. Sprinkle pecans with a bit of salt, if using.
Bake for 20-30 minutes. Stir after 15 minutes to separate pecans and encourage even baking.
Cool on a wire rack, then break up. Store in an airtight container.