Lightly greased a large rimmed baking sheet; set aside.
Increase heat to medium-high; add peanuts, and cook, stirring often, 15 minutes, or until mixture becomes dry. Reduce heat to medium, and continue to cook 6 to 9 minutes, stirring often, until sugar melts and turns golden. It will coat the nuts, but do not stir constantly. Sprinkle with salt and cinnamon; stir well. Spread nuts in a single layer on prepared baking sheet. cool completely; break nuts apart. Store in an airtight container up to 2 weeks.