Cafe con Leche

[Charles in Mendo]

I'm in and out of Mexico City and there is a coffee shop I like off the Socalo that only serves breakfast. I lke cafe con leche and this shop serves it by heating the milk and then adding coffee syrup to the hot milk. I've run across this in other parts of Mexico but what I've been trying to find out is how do they make the syrup, anyone know?

Regards,
Charles