Preheat oven to 350 degrees Fahrenheit.
In a medium pan, over medium heat, add one cup of sugar. Cook for a minute or until sugar begins to dissolve. Lower heat to low. Continue cooking for three minutes, stirring occasionally, until sugar is dissolved and turns into a rich amber color. Quickly add in cinnamon, stir and remove from heat.
Quickly, pour caramel into round 9-inch pan, being sure to swirl around to coat bottom and bottom sides completely. Allow to cool for ten minutes before adding in flan custard.
In a blender, add in remaining ingredients. Blend well together.
Gently add custard to caramel pan. Place pan in another pan for a water bath. Gently place in oven.
Cook for 50-60 minutes, or until fork comes out clean. Remove pan from water bath, and allow to cool for 3-4 hours.