Preheat oven to 325° F.

Combine sugar and water in a medium pan and heat over medium heat.  Bring to a boil and swirl span slowly by the handle; do not stir.  Remove from heat as soon as caramel turns amber in color.

Pour caramel into a 10-inch cake pan.  Set aside.

Combine sweet potato, milks, eggs cinnamon and vanilla in a blender container.  Blend until smooth.  Pour mixture into cake pan.

Place mold in a large roasting pan.  Pour mixture into mold.  Add boiling water to roasting pan, filling approximately halfway. Lightly cover with foil.

Place roasting pan with mold in the oven and bake for 80-85 minutes.  Remove from heat and let cool in roasting pan with water.

Remove mold from roasting pan, cover tightly with foil and refrigerate 4 hours to overnight.

Run a small knife around flan edges.  Gently shake mold to loosen flan.  Place a large plate over mold and quickly turn upside down for flan to drop onto the plate.

Decorate with pecan halves, slice and serve.