Clásico Eggnog

WHISK together milk, sweetened condensed milk, egg yolks, coffee granules and 1 teaspoon cinnamon in medium saucepan. Cook over medium heat, stirring frequently, for 15 minutes or until mixture reaches a gentle boil and coats the back of a wooden spoon. Remove from heat; add rum and vanilla extract. Serve at room temperature or chilled topped with sweetened whipped cream and sprinkled with cinnamon.