1 cup Sugar
Preheat oven to 350 degrees F.
Bake chestnuts on a baking sheet in middle of oven until slightly dried.
Cook sugar in a dry 10- to 12-inch nonstick skillet over moderate heat, swirling and shaking skillet (to help sugar melt evenly), until caramel is deep golden.
Remove from heat, then prop skillet up against a ramekin or metal cookie cutter, tilting it just enough for caramel to pool.
Add 1 chestnut to caramel and evenly coat by turning with 2 forks, then transfer with forks to a sheet of foil to cool.
Coat remaining chestnuts in same manner. (If caramel starts to harden, melt over moderately low heat, stirring.)
Once completely cooled, peel chestnuts from foil.
Caramelized chestnuts can be made 8 hours ahead and kept in an airtight container at cool room temperature.