Preheat the oven to 350 degrees Lightly grease 4 Ramekins.

Let the cream and egg come close to room temperature before starting.

In a blender, combine the condensed milk, evaporated milk, heavy cream, cinnamon, vanilla and eggs. Blend until smooth but not whipped. Set aside.

Add the sugar to a nonstick skillet over medium heat. As the sugar begins to melt stir with a spatula to prevent it from burning until it becomes a smooth caramel.

Stir in the whiskey and continue stirring 1 to 2 more minutes.

Lightly stir the contents of the blender and evenly pour into the Ramekins. Place the Ramekins into a large cake pan or casserole dish. Pour boiling water into the dish until it reaches about ⅔ up the side of the Ramekins.

Place the casserole dish with the Ramekins in the oven and bake for about 45 minutes or until an inserted toothpick comes out clean.

Remove the casserole dish from the oven, but leave the Ramekins in the dish for 10 to 15 minutes. Remove the Ramekins from the water and let cool to room temperature. Chill for at least 2 hours. As the flan chills, it will change in consistency slightly. A 2 hour chill creates a softer flan while chilling for 4 hours or longer will create a more cheesecake consistency.