If you have the time and patience to make the Dulce De Leche Syrup rather than using the condensed form, here's the instructions.
Combine all ingredients in sauce pan and stire
Bring to boil, reduce to simmer and let sit unconvered, while stirring occasionally to avoid building up a layer
When the mixture is caramelized and thick (roughly 90 minutes), add vanilla syrup
This recipe will make about 1.5 cups, which is good for about 3 servings of the recipe above.