The cocoa butter and solids that flavor all types of chocolate have a remarkably earthy flavor, which makes chocolate pair well with some unexpected flavors, like cumin.
Cumin’s earthy, citrusy brightness pairs extraordinarily well with chocolate and can lend a pleasing complexity to recipes featuring chocolate, like certain styles of Mexican mole.
Mole, a type of sauce commonly used in Mexican cuisine, often makes use of this combination, most notably mole poblano, which uses cocoa or chocolate to give it a deep, rich color.
Cumin can also be a great complement to a sweet cup of cocoa, and it can be combined with spices like cinnamon and chili powder to make cocoa Mexican-style.