Mix sugar, cinnamon, and salt together in a bowl. In separate bowl, whisk egg white and vanilla together in a separate bowl until frothy. Add pecans to the egg white mixture, then add sugar mixture and stir til pecans are evenly coated. Spread coated pecans onto a baking sheet.
Bake in the preheated oven, stirring every 15 minutes, until pecans are evenly browned, 1 hour.