Boil the sugar and water to the soft ball stage. Remove from heat and stir in marshmallow cream and vanilla. Add pecans, if desired. Let cool 5-10 minutes. Drop from spoon onto wax paper to cool. If the pieces run and are smooth, let cool for a couple more minutes before dropping any more onto paper. The pieces should be fluffy when dropped, not runny. Place peppermint on top of each piece if desired, as dropped. Let cool 30 minutes and enjoy!