In a small bowl mix the sugar, cinnamon, and salt together.
In a large mixing bowl, whisk the egg white and vanilla together until it is frothy.
Add the walnuts to the egg white froth and toss. Then add the sugar mixture to the walnuts and mix until all the walnuts are evenly coated.
Evenly spread the walnuts onto a baking sheet. Bake for one hour or until brown. Be sure to stir the walnuts every 20 minutes.