Preheat oven to 350 degrees.
Prepare a water bath by placing an 8-inch round cake pan in a 13×9 baking pan. Fill the outer dish with hot water to ½ inch depth.
Heat sugar in a small saucepan over medium heat, stirring constantly until melted and golden brown; Pour into 8-inch pan. Remove 8-inch pan of water; working quickly, swirl melted sugar around bottom and sides of the round pan to coat. Return the dish to water.
Add chocolate and evaporated milk to a medium microwaveable bowl. Place in the microwave for 30 seconds. Stir the milk and chocolate together. Continue heating the milk, 30 seconds, at a time and stirring until the chocolate is completely melted.
In a blender, combine chocolate milk mix, sweetened condensed milk, eggs, cinnamon and vanilla. Pour the mixture into the 8-inch pan with the caramel layer.
Bake for 50 minutes or until a table knife inserted in the middle comes out clean. Cool on wire rack for about 30 minutes and place in the refrigerator for about 4 hours to cool completely before removing from the pan.
Run a knife around the edges of the pan. Invert a serving plate over the round pan, hold tightly and quickly turn over. Gently, shake the mold to release.
Keep refrigerated until time to serve.