Vendors cook the corn kernels with a sprig of epazote, an herb with a flavor unlike almost anything else in Mexican cooking, which is what gives esquites their distinct background taste next to grilled corn on the cob.
Corn kernels are simmered off the cob with epazote until tender, then spooned into a cup and topped with crema, cotija cheese, lime, and chile powder or hot sauce, eaten with a small spoon. Street carts throughout Mexico City sell it as the loose, cup-based counterpart to corn-on-the-cob elote.