Mix sugar, cinnamon, red pepper (if using) and salt in a small bowl. Set aside. In a medium bowl beat egg white and vanilla until foamy. Add nuts and stir to coat. Add spice mixture, toss to coat nuts evenly.
Spread nuts in single layer on a lightly greased baking sheet. (Tip: line with foil for easy cleanup.).
Bake in preheated oven for 1 hour, stirring after 30 minutes. Cool slightly and break apart. Cool completely. Store in an airtight container up to 2 weeks.