Atole
Mexicans love corn. It’s grown locally, cooked and eaten as it is, processed into tortilla and other breads, and even used to make drinks. Yes, you read that right, corn is used to make drinks.
Atole is a sweetish drink that is made from corn. It is made thick, served warm, and at its most basic is sweetened with sugar. Aside from the basic sugary sweetness, there are a variety of flavors available, with the popular ones being chocolate, vanilla, and honey.
Being a popular local drink, it should be easy to find. There are even instant versions of Atole available in grocery stores all over Mexico. Just add hot water, and you have Atole.