In a medium saucepan, combine 1 cup sugar, 1/2 cup light corn syrup, 3 tablespoons water, and 1 teaspoon ground cinnamon; stir to blend.
Set the saucepan over medium heat. Stir until the sugar begins to dissolve, then bring the mixture to a boil. Once boiling, continue to boil while stirring constantly for 2 minutes.
Remove the saucepan from the heat and let the syrup cool for about 5 minutes.
Whisk in 1/2 teaspoon vanilla extract and 1/4 cup evaporated milk until smooth.