The main ingredient in the Mexican drink atole is corn. More precisely, traditional atole is made from masa, a corn-based dough or hominy flour, mixed with water and heated until it becomes thick and smooth.
Atole is a hot beverage with deep Mesoamerican roots. Its name probably comes from the Nahuatl word ātōlli. In Mexico, cooks commonly sweeten it with piloncillo, an unrefined cane sugar, and flavor it with cinnamon or vanilla. Fruit flavors such as guava are also popular.
Atole is often served alongside tamales, especially during Día de los Muertos and Las Posadas. A chocolate version is called champurrado, although the names can overlap in everyday use. The drink may look like a thin porridge, which is why it is especially popular as a warming breakfast or evening drink.
Barley, wheat, and rice can all be used in other hot cereal drinks, but they are not the defining base of traditional Mexican atole. The corn-based masa is what gives atole its characteristic body and connects it to older Indigenous food traditions.